I'm in love but I shouldn't be, please help!?

About 8 months ago I posted on here that I was in love with my professor and had been for six months already. Well, here we are, I've known her for quite a while now and I'm still as desperately in love with her as ever. I've tried avoiding her (taking cles she doesn't teach) which did nothing to lessen the feelings, I've tried to turn my attention to other people but I'm phobic about relationships (except for this one person, who calms me with just her presence). She has absolutely no idea how I feel for her, except for the fact that I go red, get nervous and usually end up making an idiot out of myself. I don't even know if she's gay! I'm not in any of her cles at the moment but see her in the corridors fairly regularly. I'm nearly 19. But I'm really really shy, like for years I wouldn't even talk in cl and when I first met her I was going through a particularly bad time. I suffer from severe depression and suicidal behaviour but when I'm near her everything seems better. What should I do??? Please help me.