Please tell your parents and let them know you need to see a therapist to help you. I wouldn't normally say that without knowing your relationship with them, but you've indicated that you feel you should tell them or something might happen. That's a healthy part of you wanting to reach out and shows you trust them enough to say something.

You have so much to gain by dealing with this now and not finding harmful ways to cope. But do be honest with them and let them know you need professional help, that this feels too big to handle alone or just within the family. You are worth it.