There are recommendations for dealing with having to pee at night. I don't remember what all of them are (ask your doctor), but I know part of it is to not have anything to drink for about three or four hours before bed.

As for your weight, it might help to reduce caffeine, if that's a problem. You say you eat healthier and exercise, but do you count calories, watch fat intake, things like that? Here's a link to a free list of fat-burning foods. Maybe that will help. Good luck--I know being overweight sucks!