Molested at 7 years old

Me and my mom has a rocky relationship. She has always treated me different after I turned 15-16 years old. I was very close to my dad’s mom and I think that’s why. They never got along too much. …I was molested by my mom’s boyfriend sister in 1993. She dated a guy when her and my dad broke up. I was 7 she was 12-13. My mom recently started back dating the same guy from 1993 after she left my dad a couple years ago and all the bad thoughts came back about what happened to me. She lives with him in the same building that it happened in. I confessed to my mom what the girl did to me and i also confronted the girl. She sent me a message admitting to what she did and how sorry she was and how much she hated herself for it and that if I ever see her and she says she’s sorry that I will know what’s she sorry for. Whatever….told my mom and I sent her screenshots of our convo and she was upset . I guess not too upset because she is still friends with the girl on social media and my little sister is friends with her too. I don’t understand how she can do that and not care how I feel? I’m so hurt and just wanted her to have my back . I would never associate with someone who molested my daughter . Her boyfriend tried to commit suicide the next day after I told my mom what happened. He wrote my mom a note saying he’s not to blame for what his sister did to me and he does not want to loose my mom. He’s an emotionally abuser. Instead of coming to see me the next day after I told her this big news she’s in the hospital with him. I have a daughter as well and if she told me someone molested her and I know the person I’m cutting them off entirely …just feel like my mom does not love me