In love with my best friend..whose gay. Please help?

Ok long story short, I'm a straight male and I'm in love with my bestfriend who is a gay woman. I didn't know if she was gay or bi so I made a move, and she said she was gay, but she "hated that she kinda had a crush on me too". But in the past, albeit when were drunk, she tries to have sex with me and makes out with me. She also says that she can never marry a woman and when we are 22 we are getting married. And she isn't joking, she's serious. I love her more than anything, I've told her that I'd do anything for her and all I want is a serious relationship, even if it's not with her. And she says she looks for the same relationships But she just goes and dates douchebag chicks who just want to have sex. I'm so confused as to whether possibly she is going through a phase, if I have a chance, or just end the relationship because I've tried being just friends and it doesn't work. I also just don't understand how she can just ignore the fact that I would give my life for her. It's really making me question the term "bisexual". Because, I would never have sex with a man, but I would marry one if he and I both felt that we deeply cared for one another, as me and my friend do. So is she gay? Confused? Bi? Does that make me bi? Or is bisexuality about sex? And do I have a shot or should I let go? I'm at the edge of my rope. Sorry I couldn't hold it all in anymore, I know it's alot to read. Any info would help. I mean look, I can't sleep cuz all I think about is this all day.