please help me with racing thoughts asap :(

Hello,

I can't stop thinking about things that have happened in the past. I am 53 years old and I still dwell on things kids have said and done to me when I was a child myself/teen/young adult. If I am busy I can distract myself, but when I try to relax, sleep, I lie there thinking "why did they say that, why did they do that?" "why didn't I say something back, why didn't i stand up for myself" My emotions go from feeling sorry for myself to thinking how I want to get revenge and I play out scenarios in my mind on what I should have did. I try so very hard to forgive, but then I am like I am never going to forgive. I also suffered from childhood physical, emotional and verbal abuse at the hands of my mother (both parents have passed now) Part of me hates my mother the other part misses her because when she wasn't mean she was a good mother (I think she was bipolar just undiagnosed back then) I cannot move forward in my life, I keep dwelling on bad things, and also keep thinking about the good times I had in the past and how life was so much better when I was younger and I cannot accept getting older. My thoughts race in all different directions. Its one part of me wants to forgive and move on the other part is saying no way no how we are holding a grudge. Someone please recommend what I should take. I am in therapy, not helping. Thank you in advance