I agree, there's no way you will loose all your weight by spring break but you can be looking and feeling better by then.
Everyone is different, but in general the more you have to loose the more quickly it comes off. I'm 5'3" and also started at 205 lbs. I lost 50 pounds in 6 months and 1 week on South Beach. I rarely ate off plan (Thanksgiving, Christmas, birthdays, were the only times and I didn't go crazy on those days, I had small, preplanned portions of off plan treats) and I exercised faithfully but didn't spend hours at the gym or anything. Mostly I just walked outdoors or on the treadmill and did the wii fit strength and wii fit step. I'm 30+ years older than you are, so you've got the advantage of youth and a better metabolism on your side. I know you've also got the disadvantages of a tight budget and the stresses of college, but I do believe you can do this if you choose to.
My advice would be PLAN your menus in advance and stick to them no matter what. Be prepared. Keep nuts or string cheese or something in your bag or in your car so you're ready for the unexpected. I relied heavily on SF gum, not only does it keep your mouth busy but it tastes good. Exercise every day, even if it's just 10 minutes. The longer you can stay gung ho the more successful you'll be and the better you'll feel about yourself. Each time you eat an off plan meal or skip the exercise makes it easier to give in the next time. There's something about telling yourself, "I've gone ____ days without cheating, I don't want to blow it now" that makes you feel strong and in control. Good luck!
