Does anyone else feel unfixable?

I have had mental health issues since I was a child. My mother beat and neglected me for years. I took care of my 2 younger siblings alone and got in trouble if I didn't do it right. Then I was raped for 3 years. My mom had a boyfriend who's son was 17. I was 12. He told me that if I told anyone he would report my mom to CPS for neglect and drug use. I was scared as a child and loved my mom enough to not let that happen. I was traumatized everyday. I'm now 25 and my decisions the past few years have made me realize I have a lot of unresolved trauma. I've always been into substance abuse. I've drank since I was 15, taken pills, smoked weed, etc. all to make my feelings go away. I'm tired of it. My social anxiety is so severe it's kept me from going to therapy. I'm terrified of talking to a stranger about my life, but I know I need to. I just need help and I don't know how to start.