A little BG: I've been with my BF for almost four years (only broke up twice, both times necessary for safety reasons) and have a two-year-old son by him. Our first engagement didn't go well (hence the second breakup), but we are still wanting to get married. Our wedding was supposed to be the 30th of this month, but oh well; I have to stay optimistic.
So I didn't actually buy my dress...or the veil. Both were donated to me by a complete stranger, whose daughter had recently tied the knot and no longer needed them. I was moved to tears, and i love the dress. There's just one major problem.
IT DOESN'T FIT ME. IT'S A SIZE 10. I'M A SIZE 14 OR 16 NOW.
I'm very worried about it fitting or NOT fitting in this case, because i do intend to wear it on my wedding day. I'm a part-time college freshman and a full-time single mom, so going to the gym isn't much of an option. I had to drop one of my three classes to utilize the exercise equipment. Fifteen minutes on the treadmill, ten on the elliptical (working towards thirty), and i try to do as many sit-ups as my body can tolerate. I feel the burn, BUT i can only do this twice a week (if my mom ever knew, i'd never hear the end of it).

This picture is fairly recent but as anyone with eyes can see it doesn't fit. I was feeling okay that day so it hardly bothered me, but the next day it hit me like a freight train going full speed around a tight corner. I'm often asked if i'm pregnant, and that doesn't help the fact that i already have low self-esteem. WHAT SHOULD I DO?? I can't drop another class because i'm on FASFA, but if i wait for next semester it'll be near impossible to lose that much weight (and i'm already 180 lbs, 40 more than my post-pregnancy weight).