Anger issues!

I'm in high school. I've been with my boyfriend for almost two years. And recently, I've had tons of mood swings. And I am a huge jerk to him. He doesn't even do anything. And I'm always so mean. And I try to stop, but it's hard. I don't want to be mean to him when he doesn't deserve it. He's always so sweet, and he puts up with me every day. I feel like he deserves to be treated equally. Not the way I treat him. I love him to death. I don't want to affect our relationship negatively anymore. I just get mad at little stupid things. I don't know what's wrong with me. Can anyone give me tips on what to do to stop getting so mad about small things? It makes me feel terrible!