Hello! Welcome to 3FC. This place is amazing and the people here are absolutely supportive.
I know what you mean about studying so much and putting off exercise. That was totally me before the two semesters before this. What I do now is make myself wake up earlier to exercise before class that way I have all of the day AFTER class to get my studying done.
I know that doesn't sound like a pleasant thing, and at first it was horrible. I won't lie. Haha. But, now I look forward to waking up and getting myself pumped before school. I've found that I'm happier and more awake on the days that I exercise than on the days I don't. So that's one thing you can do.
Also, how much soda do you drink? If you drink more than one can a day, you might want to try limiting yourself to 1 a day. And then after you're okay with that, try and eliminate it completely. I used to be quite a soda fiend myself, but then gave it up for Lent. I just lost my taste for it. The only soda I'll drink now is root beer, and even that is a very rare occassion. Very very rare occassion. Haha.
I hope these tips help you at least get started.
And I'm sure more ladies (and a few gents!) will follow my post with more helpful tips!!