Saying no to showing your self harm...? Please help me!?

My parents know I self-harm. And they keep telling me that depression or bi-polar doesn't exist and how I just want attention. They also said im trying to show them how I hate how they made me move and want sympathy. (Even though I started self harming three years ago, and we moved six months ago!) But the problem is, I dont even know why I self harm. Its like, I cant explain it! Each time my shorts ride up while im sitting, or my shirt pulls up as I'm grabbing something and a cut is visible, they will pull it up and look at it and yell and scream at me. "We arent moving back anytime soon!" "Stop being a little attention whore!" which really is not helping me. How can I tell my parents to stop doing this, almost each time after this happens it makes me want to self-harm more. They also talk to me like I'm to blame, Please help me. :( I already see a counselor who told them I need anti-depressiants but they wont listen.