Im 11 depressed mad and cutting. What do I do ?

I started cutting in December then I stopped but started again on my B-day (June 3rd). No one knows about it but my Best Friend. My parents treat me like I'm their servant/maid, and there always fighting around me and smoking around me when they know I'm allergic to smoke and dust... They also blame every ******* thing on me. I've also been eating more then I should (no im not on my period) I haven't gone out anywhere like out with my friends or what not since January. My mom caught me talking to my best friend about the cutting and she said she'll put me in the nut house if I do and she catches me. What do I do ?