What is wrong with me? how i deal with people...

I am antisocial so people don't get close to me so I don't hurt them. I always think of other people as games, someone to toy with, mess with, and I do. I can't stop, it automatically happens when I meet someone. I turn into something I'm not and they end up loving me, and I break their hearts. I keep to myself in most cases so I don't hurt people; I don't enjoy it, but I can't stop. I also accidentally cause physical harm to those who are close to me (another reason why I try to be antisocial); I'm significantly taller than those around me and in good shape. When someone gets close I let down my guard, I stop trying to control my strength, and I hurt them because of it. The only other time I cause physical harm is when I'm pushed over the edge. I've been pushed over the edge and hurt someone. He insulted me; I didn't care; He insulted my family; I got angry, but controlled myself; He insulted her, my only friend; I attacked him. I broke his nose and and probably a rib or two. I also punched my teacher that day who tried to pull us apart, but in my rage I accidentally hit her when she tried to pull us apart. My sanity came back and I was dead inside. The real thing that's driving me insane is my friend. I may be in love with her or it may be my mind making me mess with her. Now I try to keep her farther away, but lately, I've been messing with her mind. Now she is always sitting next to me and I can't stop messing with her. I don't know if I truly love her or if I'm just going to hurt her. I really do care for her, and most people, so I try to push them away to protect them. I hate myself for this and I'm secluding myself for Spring Break. I can't go back and sit next to her not knowing if I'm going to break her heart.