Can someone help me get motivated to lose weight???? :(?

My mom is a personal trainer. When I lived with my parents, I was in perfect shape. i used to go to the gym every day and work out, play sports, etc. Well, I left for college, and now, I have stretch marks EVERYWHERE and have gained 42.6 pounds. :( I can't motivate my self to lose the weight...I can get myself motivated for a day, but when I wake up in the morning, I just forget and eat something bad. I haven't hung out with any friends from the dorms or from high school in a year....I've heard from my twin sister (who is still in good shape) that they all ask if I'm pregnant or just fat when she hangs out with them. I don't want to see anyone until I'm looking good again!! ....but it is taking so long ....its been about a year since I have seen anyone but my boyfriend & occasionally my sister or my dad. I know my friends will always love me no matter what i look like and i shouldn't think this way, but i am just so embarrassed. I don't have any clothes that fit me anymore either!!!! i don't want to go shopping until i can fit in my usual sizes. I am a poor college kid struggling to survive--the last thing i want to do is spend a bunch of money on clothes and then lose weight and not be able to fit in them! I used to be so fashionable--now i only wear shorts and t-shirts and use the fact that I work with animals as an excuse. I have a gym membership. My apartment even had a 24 hour fitness center.....but I don't go anymore. I spend all day before work looking in the mirror and being sad instead of working out :(. the worst part is, i KNOW the fat will come off very easily!!! A few months ago, I lost about 20lbs, but then my car broke down and I couldn't get to the gym. It was FREEZING outside, so i didn't want to run....I kept saying i would just start working out again when my car was fixed, but by that time (months later), I had gained all of the weight back. My boyfriend is one of those people that can eat ANYTHING (i.e. 10 large pizzas with double cheeseburgers on top .....7 times a day!!!! [obviously an exaggeration haha]) and won't gain anything!!! He never works out at all either. EVER. I always ask him if he will work out and eat right with me, but he's like "HA, YEAA RIGHT!" ....i know i shouldn't need him to do this with me to feel motivated, but its so hard watching him eat stuff that looks so good haha, or making two seperate meals all the time, or going to the gym alone when i would rather spend time with him. Please help me....I'll probably keep adding more details, but.....I feel like this is already annoying to read through. OH! PS. I used to have the HIGHEST self-esteem in the WORLD. ...now...OBVIOUSLY i dont lol