Just be glad you're getting out and away from her…the crush should fade in time.

I'm going back to school for three years and I'll be spending ample amounts of time alone and in general around the professor I have a crush on.

And as far as post-graduate depression goes, I was horribly depressed before I even finished my masters and I'm depressed about graduation before I even START my doctorate. For me, my life ends after school. I've known nothing else and my only hope is to stay in school by becoming a professor. But since that's practically impossible even though I'll be focusing on 3-4 areas in my department, my life probably is over…nothing else to live for. So you're not the only one to feel this way. If our economy were only good enough that people could make a living, especially if they spend most of their life becoming an expert in their field, then maybe there would be a reason to continue living after graduation.