i want to stop cutting

Pressure at school is getting to me, my own teacher calls me stupid!!!! And the principal does nothing about it! Last time I cut was a little less than three days ago, I thought I had stopped before but then school kicked in full force- So much stuff got in my head and I slipped- I grabbed my knife the other night and before I knew it I had six new lines on my wrist. Now I know that’s not alot- and it’s much better than I used to, but my principal found out last time and told my parents, and the entire school found out! My parents didn’t believe it thank god, but what made it worse is that the school found out because the principal was dumb and grabbed my arm in the middle of the cafetiria and looked at my wrist! My friends all denied that I do, and even came up with a story to keep my parents from finding out- but I had to promise to stop.
I’m starting up again and I’m afraid that they’ll find out. I origanaly started cutting because pressure was so great that I think I just snapped and, well I don’t remember a lot but next thing I knew I was using base on my arms to cover up my cuts. Basically I just need a place I can talk about it and my parents not know- I think they’ve read my journal- and I don’t think my friends listen to me… I know my parents don’t… and the only adult I trusted moved, the other one betrayed my trust… so I don’t know but this might be my last resort.