---"hey, you're still young...enjoy the college life...it goes by so quickly, never to return. And, btw , you don't have to worry so much about your weight until you turn 30... then your metabolism goes blatooeee... and you can gain weight staring at an apple."---
I agree, have a good time and don't worry so much about it. Seems like you already exercise and tend to know what to eat. But have some pizza and beer now and then, you'll survive :)
I'm 40 now and I've gained about 5 pounds since I got out of high school (I'm 175 now). I eat right, AND I eat total crap now and then, I drink beer, hasn't killed me (or made me fat) yet. Oh, and today I could probably beat the crap out of 18 year old me back in 1983.
So even if you do gain a few pounds, it's not the end of the world. Your real friends (and girlfriends too) should like you for you, not because YOU think you're hot.
My gf has about 20 pounds on me and calls herself fat all the time. To me, she is absolutely beautiful! It's all a matter of taste. Ever seen a big guy walking along with a girl and wonder what she sees in him? He's probably a good guy and that's alot more important that looking like a pic in a magazine.