I feel like im drowning, do i even have to reason to?

When i was 8 a family member and i were playing doctor and they touched me. i was so uncomfortable but they said it was okay because we were family. They were only a few years older than me and i know children can abuse other kids but i dont know. I was old enough to know it was wrong but too young to fully understand, maybe they didnt know what they were doing? But i cant stop thinking back to that moment, i feel so sick and disgusted and helpless. It was just a small touch but i feel violated. If i were a parent i would be furious to find out that happened to my kid! But i still feel like its not valid enough to be hurt by. I dont know what to do anymore, ive never told a single person and it feels like im drowning. I cant tell anyone, its such a stupid reason to be upset over, and it would ruin their life. Even on an anonymous website i feel so much shame i cant even talk about who they were