Well, probably not 30lbs. lighter. But probably, ummm, how much does a gall bladder weigh, again? 
Okay, here’s my story, and yours is gonna be a lot better because it’ll probably be done laparascopically: about 19 years ago, some pretty serious pain started during an episode of L.A. Law. By the time the show was over, the pain had progressed from “pretty bad” to “horrifying”. I was so sick that I told my hubby I couldn’t go to the hospital because I was literally unable to get dressed (I was watching TV in my nightgown). He bundled me into my robe, put a pair of his socks on me, put me into my mother’s wheelchair and got me into the car and to the hospital. By the time I got into the car, in addition to the excruciating pain, I was throwing up yellow stuff.
The ER was very crowded; the first doctor to see me wanted to give me painkillers and send me home! I said “No way”. In my mind, they could either do something for me, or just kill me. But I wasn’t going through that pain again! The second doctor said “Well, we can list this as elective surgery and remove your gall bladder two weeks from now, or we can list it as emergency and do it tomorrow”. I said “the sooner the better!”
Not only did I have to have mine open (lap just wasn’t widely available at the time), but they had to cut me extra-long because my gall bladder was so distended it had partially adhered to my rib cage.
Recovery from abdominal surgeries (I’ve had five now, so I should know) are infamous for being very tender. However, there are things you can do to help: one, find out what your doctor’s pain relief protocol is. You surely don’t want a surgeon who’s stingy with pain meds when you’re right out of surgery. Two, ask for a “trapeze” above your bed. It will be amazingly helpful in repositioning yourself, and getting up. Three, get up and walk asap, even though it will hurt like hell. Time your walking with your pain shot. If you’re getting morphine or demerol, plan on walking about 15 minutes after your shot. If you’re getting dilaudid, plan on walking about 5 minutes after your shot. This way, the pain reliever is in full swing, and is still going strong when you get back to bed.
The really good news is, as much as it hurts at first, it improves rapidly. The first four abdominal surgeries I had, I was off narcotic pain relievers by the third day (my last surgery was a lot more complex, and required narcotics for longer). So just keep reminding yourself, not only is it going to get better quickly, but it’s never going to be as bad again as it is right now!
I’ve known a number of people who’ve had the lap procedure, and apparently, it’s much, much easier than open.
Good luck!