It is hard to let people in especially when suicidal thoughts or self harm thoughts come to mind. It seems like your parents don't really know how bad it's getting.

If I was in your shoes I would for sure find someone to talk to, a counselor or just someone that can help you with what your feeling. For now, start talking on here. But for now, looking up ways to keep calm, ie breathing exercises, meditation, exercise. really anything that could help you when suicidal thoughts come up.