Is it normal that i have these obsessions?

I sometimes realize that I am starring at someone, usually there shoulder, back, or neck, and have this urge to bit someone. Its been an urge Ive had since I was a little girl, and sometimes, it gets so bad, I bite myself. I've never drawn blood, but I have some marks over my arms. I also get these mood swings, were I am white hot with rage, my vision goes blurry, my eyes hurt, and I want to jump someone.
Just a little tid bit, I am also obsessed with serial killers. I wish I could have met Jeffrey Dahmer, not to like say how awesome he is, but just to get inside his head. I also love bones, and will hopefully one day work with ancient remains.