How do i stop masterbating?!?!?

Hi, im 12 years old and am masterbating. I've tried, but i cant stop! I started when i was about seven. It started when the jet in the pool in a "sertane" spot (srry if this is wierd). I then got anxious when there wasn't a pool around. So i started (with pants on) rocking back and forth on a chair. I know it's perfectly normal, but i WANT to stop. It's not very good for my mental OR fisical health. Im begging u, PLEASE HELP ME!!!!😭😭😭