You have many, many reasons to be upset. Sexual abuse, bullying and warring parents can make a kid feel very unsafe and insecure. It’s no wonder to me that your feelings are all over the place. All of the behaviors you are worried about look to me like ways to you are trying to feel more in control when life feels unpredictable and even dangerous.
Lying and manipulating people may be a way to try to have some control. So is hurting yourself. Wanting to hurt others may be yet another way that you are telling yourself that you are deeply hurt.
The healthiest part of your letter is that you want to “fix” yourself. I agree that there is something to fix. You deserve to be more at peace with yourself and to take better care of yourself. I think you need to see a therapist who can help you sort out your feelings and who can support you as you deal with your complicated past (and present).
Since you are in your senior year, you are at a transitional time of life. This is an excellent time to take charge of yourself and get the help you need. Find a therapist so you can work on getting ready to leave home and to establish a healthy adult life.
I wish you well.