I basically went through the same horrible experience you did almost 40 years ago and yet it sometimes feels like it only happened yesterday. I relive all those bad feelings, but with it I also carry a lot of hate. Hate towards my late mother because she confronted the guilty party when I condifed in her and at the end she chose to believe HIM instead of me. I can be wrong, but I think you feel the same. Betrayed by your mother. How unfair to have to deal with that too.
Unfortunately I don't know what to tell you to make it better or ease the pain as I haven't figured it out myself yet. All I know is that we need help. To get rid of this monster that dwells inside us.
What you don't let go of, you have to carry with you. Easier said than done though. You'll know.