Hey!! I appoint myself as the PERFECT girl to answer this question
I lived in the dorm for two years, and was really overweight (all my life) but couldn't lose weight because I could not resist the temptation of all the stuff you could buy in the dining hall. Honestly, I would eat about 4 huge meals a day, and then at night we'd go down to the convenience store thing and buy tons of junk food snacks. No wonder I was fat lol.
As soon as last school year ended, I said bye bye to the dorms/dining hall food in front of my face, and lost about 30 pounds by becoming a gym addict over the summer lol.
Moving out of the dorms was the BEST THING THAT COULD EVER HAPPEN TO ME, because for the 2011-2012 school year, I moved into my first apartment on campus, and I have been able to keep that weight off and lose even more. Because I am eating my OWN food, not tempting chips and cookies and pop that I can have for free.
My advice to you, is that because you still have this semester in the dorms, GO TO THE CAMPUS GYM in the evening time when you'd normally eat. I do this every single day, and I save myself so many calories. I was always too shy to go to the gym, but now it's apart of my life.
Hope I could help.