Put another way, if I know it’s going to be a rough day I don’t wear my favorite clothes, because I’ll have a mental association with that day and won’t like them as much. Is this weird?
Not sure whether this is what you meant –
Some of my days involve getting greasy and/or muddy and others involve showing up at a town meeting; so that’s definitely going to affect what I wear (though it may involve changing clothes in the middle of the day.) The weather also strongly affects what I wear, both because I spend a lot of time outside much of the year and because the temperature in the house varies significantly with the weather outside, though not nearly as much as the outdoor temperature does.
If what you’re asking about is only emotional issues: I think I’m more likely to wear something I particularly like on a day I’d expect to be upsetting, because I’d take a bit of comfort from, say, a favorite shirt given to me by somebody who cares about me.
I don’t think any of this means that you’re weird; or, at any rate, weirder than humans in general are weird.
I dress for the temperature, both indoor and out. And for the (in)formality of the venue or whoever I’m meeting with. And for the activities planned.
Dressing for my emotional state? Never would have thought of such an idea.
I guess if I’m expecting a rough day I’m likely to wear clothes I think of as “workhorses”; in other words, they may not be my favorite but they’re comfortable and don’t require any further thought.
On a slight tangent, when watching movies or news or what-have-you, and they’re showing a person who’s been through a disaster of some type, I tend to look at what they’re wearing and think, “when they put that on, they had no idea what was in store for them”.
That’s why Mom always said to wear clean underwear. 
I dress for work or social requirements, and for the weather, but not for mental state.
Having said that, I don’t think what the OP is describing is weird.
Cf. the old, old joke about brown pants.
Mom always said wear clean underwear in case you’re in an accident but I thought that’s what an accident was???
To answer the OPs question, not for a day in general but for a day specifically, meaning I don’t dress up/down on, say, Tuesday but this week, I was out late on Mon night & am dragging a bit, I have a meeting I really don’t want to be a part of at work & I have something after work that I have to do but don’t really want to; therefore, when I get dressed on Tues, in addition to dressing for the weather I’ll probably choose a ‘meh’ shirt instead of my favorite ones.
I have a specific shirt I wear each workday (I’m wearing my Friday shirt right now, and if it were in the wash for some reason, I’d be vaguely unsettled all day wearing something else), but that’s my ASD brain calling the shots there…
Beyond that, I just dress for the weather.
If I were to dress for my emotional state I would be lurching throught the door in my pajamas.
Which I actually did one day many years ago.
I tried to pass myself off as wearing a “nicely coordinated outfit” but the receptionist’s comments guilted me into driving home to change.
Hoodie, clean shirt and jeans, seasonally appropriate shoes, coat and I am good to go.
The majority of the time I am in purely practical clothes for working outdoors, or in more presentable clothes when I am going to town or to church. Sometimes there’s a holy day at church which calls for something extra – pale flowery colors for Easter, somber for Good Friday. When I sang church gigs I used to keep funereal and wedding outfits to sing in – restrained and modest of course.
I do wear certain accessories when I think I’m going to have a hard time, like a bracelet made by a friend.
One of the few ways that I am organized, is that before I go to bed I set out my clothes for the next day.
So by definition it won’t reflect how I feel in the morning, and has been picked for purely practical reasons (weather, what things I’ll be doing that day).
I think it’s so that if you’re found in a accident people aren’t staring at your dirty drawers.
In my retirement, I dress only for (a) staying at home, (b) going out shopping or to a movie or a sporting event or some other casual thing, or (c) going out for some special occasion.
(a) generally means a bathrobe, or if one prefers a more distinguished term, a “smoking jacket”, though I don’t smoke.
(b) means a T-shirt and jeans with appropriate outerwear that depends on the weather.
(c) is a pain in the ass that I try to avoid like the plague.
Retired also. I always get dressed, but if I’m going out I put on “social clothes” and if I plan to stay home I put on more ragged nonsocial clothes. It also depends on where I am going and if I’m likely to take off my jacket when I’m there.
I love that joke and think of it every time I wear my brown pants.
My duds are the same every day. Well, I might wear shorts in the summer. Cold climate, short summers.
Also, Colorado Rocky Mountains. We are a casual bunch.
I don’t work on cars much any more. Or paint rooms, but that would have me put on old jeans with holes instead of newer ones.
Nah. When you worked in tech in the good old days, you never had to buy your own T-shirt. 
I pretty much wear the same thing every day. Work pants, I’ve got about a dozen of these in different colors, t-shirt, henly and flannel in the winter. If I have a meeting, I’ll try to find a flannel that doesn’t have a hole in the elbow.
Why do my flannel shirts develop holes at the right elbow only? When using the computer mouse, my elbow is not on the desk…perplexing and vexing.