I just now joined this site and saw your post. I empathize with you as I'm a guy who was abused by an older sister. 8 years older and she was jealous of me while I was still in my mother's womb (stories from mom) because I 'stole' her baby spot in the sibling age order. "Sorry for being born sis!"
It's hard to explain to people that a sister abused a brother. I understand that dynamic, other guys tell you to stand up to her, but when you do it only makes it worse. It's feels awkward to tell other women. I was very fortunate to have a loving empathic mother. I didn't realize how much Mon held sis at bay until she died in her 80's and all hell broke loose. Feel free to talk if you need to. Our experiences may not be exactly alike, and hope I'm not putting my story into yours. I believe that everyone has a right to their own feelings without being challenged or invalidated. Feel free to talk if you need someone to listen.