Need help with my mental state

As-salamu alaykum. I'm seeking advice. Something from my childhood triggered a lot of major sins and bad habits. I feel intense guilt-it led to thoughts and acts I can't mention. I can't share the full truth with anyone; they'd see me as filthy and think I chose this, so I can't get proper help. My mental state is crumbling fast whenever I recall what happened and what I did. I feel like a stranger to myself, but many of us don’t know ourselves-only Allah knows us better. Alhamdulillah, Allah brought me from darkness into light! But the one habit He helped me quit, I fall back into when stressed or out of control. Doing it reminds me of that childhood event-since I couldn't control what happened, I can control stopping the habit, even though Allah controls everything. I'm disgusted and keep bottling it up. When I told my mother and sister, my mother thought I was joking, and my sister dismissed it as nothing. It’s a big deal-it led me to many sins-but I can't just blame the past; my own hands committed them. Now I'm lost, feeling purposeless, just bored, crying, with nothing else to do.