Is it normal to hate my best friend?

My friend and I have a history. A few years ago, she began dating this guy, a terrible guy, it eventually drove us apart. We each did and said things we regretted, and it left its scars. A year ago, she broke up with this terrible guy and we became friends again. Now, when we did this, I was terrible depressed. I had left school early and had been living holed up in my room for days at a time. I didn't even graduate. All I did was play video games and occasionally think of suicide. I was quite relieved to have her back. But now, little things and big things have started to make me hate her more steadily by the day. She's claiming she's depressed, yet, at school, she's so happy. She has a different boyfriend, who she says she is now unhappy with. She also has a guy who really likes her. I realize this a problem for her. but every time she talks to me about it, I don't care one bit, I consider it a responsibility to talk to her about it. I know she can't help how she feels, but I know what depression feels like, and I think she's reveling in her own misery. I ask her questions about it, trying to understand, but I don't. I think my curiosity encourages her. I can't understand it! She has such insecurities but she thinks she's so cute and cool. I hate everything about her, even if it's one of my qualities. I don't think I harbor resentment toward her about her previous boyfriend, not at all. It was his fault. But, she ended up talking to one of my REAL best friends (I could never tell her that, as she thinks of me as her best friend) about her problems. It made me so angry! I feel everything she asks me to do is a chore, I feel that I wouldn't care if she was absolutely miserable, because I STILL have my own problems, I hardly show it, but that's because she puts so much attention on herself. I'm not an emotional person but it seems like that lately all I can feel is hate. Of course I can't tell her all of this because it would cause even more problems, I don't want to start another war like we had with the terrible guy. She's making me feel like all I want to be is alone. Please? Some insight? I don't understand myself.