I was in a similar situation but I was younger, 16. I tried going through a trusted teacher and my school but it backfired because I was a minor and they had to tell my parents. What a mess.

Are you in a position to get therapy on your own without your parents financial help? That would be the most discrete way of doing this. Once you are 18 of course. Or if you are going to college, use campus counseling facilities.

If you need immeadiate help you could go to a regular doctors appointment and tell your dr your concerns. Being young and not having parents sympathetic to your needs is difficult, been there done that. But once you are 18 getting help with privacy is so much easier.