waterbug
I fasted twice. The first time my mental clarity was great, and I had tons of energy after the 3 day hump. The 2nd fast, was terrible, I was clear minded at first, then became very depressed and emotional towards day 6. It's different each time you fast. It is hard to say what it will be like for you.
What I would do if I was really busy with school, is try to fast, see how I feel, and if becomes too much of a problem, go back to raw foods. I tried doing a raw diet, for two weeks and felt more clear minded and at ease on it.