I know what you mean. I sometimes get the ‘what if I just jumped off’ thought - not really an urge to do it so much as an urge to stop myself doing something I unreasonably fear I might.
Driving. I hate driving. I can’t even explain how much I hate it. I have no other way of getting places (work, store, family, etc.) so I’d just as soon not go. I am in constant fear we will have an accident, the car will break down, etc.
And don’t even get me started on driving over bridges. When I lived in Cape Girardeau many years ago, I’d have to drive across this to get to the Illinois side - it was almost impossible. I still get shaky, just looking at the pictures.
For some reason, when I’m sitting on a bus, train, or plane, I start thinking about how I’m going to need to get up to get off, and then I start to think about how I’m going to get up, and then I start to worry that I’m going to muck-up getting up and trip over and make an arse of myself.
My brain is a busy place.
Not to get too off-topic about the OP, but I went through almost the exact same thing during the same time frame that you did. I used to enjoy flying as a kid. Then, I took a flight with my wife when I was about 25 and suddenly became really, really anxious about it. Panicky by the time we finally landed. And from that time on, I was deathly afraid of flying. Like nails-dug-into-the-armrest-the-whole-flight afraid. Any hint of turbulence would send me into a bug-eyed tizzy.
I realize, of course, that every case is different, and I don’t know how strongly you’re looking to overcome your fear, but just in case it helps, here’s what happened to me. Last year, for my birthday, my wife bought me a flight in a bi-plane. Some people had suggested that being in a plane where you can see out of the front and talk to the person in control of the plane would make a big difference. And you know what? It worked. It was wonderful. Not only did I get to talk to the pilot and have the wonderful view, but he let me fly the plane for the entire flight (with the exception of take-off and landing, of course). Somehow, being able to feel the turbulence while I was in control of the plane far surpassed all the verbal and written explanations I’d come across for why turbulence was no big threat to flying.
I have been on six different commercial flights since that bi-plane ride last June, and the change in me has been nothing short of miraculous.
Anyway, profuse apologies to all for the hijack. I just try to share that story with anyone who’ll listen who has ever been afraid of flying like I was in the hopes that other people will be able to get beyond it.
I can not be on the left. This has nothing to do with politics. If I’m walking side by side with someone, I have to be on the right. If there are two other people, I can have somone on my right if there’s someone on my left. When sitting at a table, I must not be the last person on the left. Booths are bad - I won’t be the first one into a booth if the second person will be on my right.
This started sometime in highschool. I noticed it when walking around at DisneyWorld. I couldn’t walk straight on the left and couldn’t carry on a conversation because being on the left was so distracting mentally. I thought it would go away, but it hasn’t.
My husband is aware of this quirk and accomidates me. With people I don’t know well enough to explain this to, I manage to work my way into a position on the right without calling attention to what I’m doing.
I’ve never met anyone who has had the same quirk. I figure as far as quirks go, it’s easy to deal with.
Oddly, I’ve found that if I wear sound-deadening ear protection, I can handsand without problems. It apparently eliminates the high-end frequencies that are so annoying.
I hate wooden ice cream paddles so much that if I see someone else using one it freaks me out. If it’s in my office I have to stop what I am doing and get them a regular spoon.
Because of the tongue-depresser taste?
Not the only one. There’s walkways that cross busy roads here, and we live right next to one. Sometimes when I’m walking over them I get this weird weak feeling in my legs and half an urge to jump… even though I would never do such a thing. Same with at miltulevel malls and, strangely enough… when playing video games. I get the same weak feeling in my legs when playing Mario and trying to leap over the spaces or if there is a lot of jumping gaps I have to do.
Probably why I have such trouble finishing the games.
Other quirks/phobias of mine:
I’m deathly afraid of my words being mistaken and either laughed at or people getting angry at me because of it. Which means I am constantly thinking of how my words could be construed, but often a moment or two behind when I say (or post) them. Because of this, I prefer to keep quiet rather than have my words mistaken, especially after an experience in high school where I realized my words could be mistaken for a double entendre a moment after saying them, and tried to correct myself which only highlighted what I was hoping they wouldn’t notice… and then I got laughed at by the whole class (this just happened to be when we were playing out a trial of MacBeth, I was Hecate and on the stand).
This also means I try to think over my posts, and more often than not many get deleted because they are either no longer relevant or I decided that they could be taken in a way I don’t want too easily and refuse to take the chance on it.
I’m better than I was, after a few years of hanging out with guys who take anything as the worst they can make it and exchanging zingers back and forth… I’m not quite easy with it, but I’m easier than I was. I have to be comfortable with the people first though, otherwise I am still the quiet wallflower.
The other one is stuff coming at my head. I am always afraid of hitting my head on things. I duck instinctively through the majority of doorways, slouch through parkades, and flinch if I see anything coming towards my head. This has resulted in many times flinching back on the bus as I stand from my seat, because the hand straps they have dangle at a level about the side of my face. I know it is there, but I sometimes forget or don’t pay attention and then when I get up I see this thing from the corner of the eye aimed at the side of my face and flinch back… a couple times hard enough to land back in my seat because I so offbalanced myself.
This is also why I don’t wear heels over 2 inches, and even that is pushing it. I prefer flats because I’m already 6’1 and adding a couple inches just makes it more likely I will hit my head, especially on buses.
I get very uncomfortable and defensive around dogs. They trigger some kind of primal fight-or-flight instinct in me; I feel like I need to be hypervigilant in case the dog should… I don’t know, attack me, I guess. I can let my guard down with an older, slower dog, but an active dog that’s running and jumping around-- forget about it, get me out of there.
Also, I’ve recently noticed that bad weather makes me jumpy. I never minded it when I was a kid. I think that home and car ownership have made me acutely aware of the damage that wind, or heavy rain, or lightning can actually do. The possibility of a tree falling and crushing my house never even crossed my mind before, now it’s the first thing I think of when I see a dark cloud.
ETA:
I get this exact same feeling too!
When I am seated in a room or in a restaurant I like to be seated where I can see the door. I’m more comfortable when I can see who is coming in and where they are going once they have entered. I don’t know where or when this quirk originated, though it probably stems from my intense loathing towards people who think it’s funny to sneak up behind me and scare the bejeezus out of me.
I get really anxious if I have to drive somewhere I’ve never been, or maybe only been once or twice. I don’t think that in and of itself is all that weird, because being unprepared or unfamiliar with the roads is a potential cause of accidents. But what it does to my poor nerves is way more extreme than it needs to be.
I’m also claustrophobic to a degree, but it’s very unpredictable when it’ll hit me. Once it hit me when I had been in a packed airplane, then in a packed compact car, holding myself together through all that, then when I got home, my husband hugged me and I freaked. Poor man didn’t know what to think. 
Reading you talk about balloons, it made me think about my own little everyday fear :
If children, or teenagers, are playing football in the street (or on the beach, in a garden/park), I’m always afraid to be hit by the ball. I always try to keep far away from these people.
I can’t stand anyone (including me !) touching my navel. Don’t know why, maybe it’s because my symbolic umbilical cord has never been cut !
It’s quite the same, but maybe less, with my eyes. I don’t like going to the ophtalmologist, and I’ve never tried to wear contact lenses because I simply can’t imagine putting them in my eyes (or out of them, it’s the same). My father wears some since I was a child, and I’ve never liked looking at him when he was putting them (excuse my bad english !)
Christ alive, you people are freaks. I thought I was eccentric, with my hatred of moths. But moths truly are horrid. The rest of you… get some therapy.
I can not go to sleep unless a fan is on. It gives me something to concentrate on as I’m falling asleep. If there is no fan making noise my brain starts thinking and it doesn’t stop thinking and I basically toss and turn and never really fall asleep for more than a half hour at a time.
Stupid brain always thinking.
Oh, criminy, me too! When I found out last year I needed bifocals, my hubby tried to talk me into contacts (he’s worn them for years). But there is no way in hell that you could get me to voluntarily touch my eyeball!! Like you, I can’t even watch him put them in and take them out!
And for the folks that have the deep-seated hatred of balloons popping, I’m right there with you!
I’m always on edge around balloons, too. I startle easily and don’t like sudden loud noises like balloons popping.
No, you’re not the only one.
I can’t put things in my eyes, either, and I tend to flinch pretty hard if anyone gets their hand near my eyes. I can’t use eye drops. I can manage if I keep my eye closed and don’t see the drop coming, but I miss a lot (it’s easier for me to give my cat eye drops than it is to put them in my own eyes- literally). I can’t wear contact lenses, hate going to the optometrist, and can’t have anyone else do eye makeup on me. I can do eye shadow, because you can close your eyes while you do that, but not mascara or eyeliner.
I can’t watch someone else putting in or taking out contacts, either, and can’t watch anything on TV or in a movie in which someone touches their own or someone else’s eye.
I can’t watch anything that’s very gory on TV or in a movie, either- I get literally nauseated. All I remember from when I saw Master and Commander is the scene where Dr. Maturin performs surgery on himself. I couldn’t watch the screen while that scene was going on (I relied on Mr. Neville to tell me when it was safe to look- he does this a lot with movies and TV shows, and he doesn’t tell me it’s safe when it isn’t, because he’s sweet and he knows he’d have to deal with the resultant hysterics and/or vomit if he did). Just listening to it made me feel like I was going to puke. Normally, before I go to a movie, I will read one of those “reviews for parents” sites to see if there are likely to be any gory scenes that will be too much for me. I didn’t in the case of Master and Commander, because Mr. Neville really wanted to see it, but I should have made him go on his own.
I’ll third this. I’ve worn glasses since I was 11, and I won’t even consider contacts. It just ain’t happenin’.
ETA: Oops…guess I’m the fourth, after Anne Neville. Ditto on her comment about eyedrops. My wife basically has to hold my eyelids open and sit on top of me to get the drops in. But at least there’s incentive for me in that case. 
If I have to change the volume on a television or radio that has a numbered scale, it must be on an even number. Weirdest thing. Occasionally multiples of five are acceptable. But no other odd numbers. It will irritate me if it’s not on an even number.
I hate watching something in a movie or TV show where the person is embarrassed or does something embarrassing. It’s been that way since I was a kid. I literally can’t watch, I usually turn my head and squeeze my eyes shut.
Within the past year or so I have developed a strange phobia while driving. I don’t like to pass other cars. When I get close to them I have this irrational fear that they are coming into my lane and don’t see me. I don’t know where it originated; I haven’t had any experiences where this has happened, at least not to any dangerous extents.
I also hate calling people on the telephone. Friends and family are usually fine. But businesses, co-workers, etc. drives me crazy. I will start to dial and hang up a dozen times. And I usually fidget incessantly while talking when I finally do get the call made.