I don't think this is in my head, I think it's abuse.
Why do you think you're being abused?
I can't give a specific reason, it's just an instinct I have.
It's good that you're being attentive to possible abuse, and if your instinct is telling you there's abuse then it's your responsibility to speak out. If you feel like somebody is being abused, then you need to report the abuse to the authorities so that they can help. If you keep it to yourself, then the abuse may continue and even escalate.
I'm going to kill my abuser.
I sure hope you're just kidding. Call the police or stay with a family member if you're being abused, do not do something illegal such as killing someone.