Did something wrong with my sister and dont know what to do?

So 2 nights ago my parents were away and I was planning a little get together with friends and invited about 7 people and ended up having 12 or so people in my house. My younger sister (im 22 shes 19) came home from work and begged to have her friends round despite already enough people I said yes and she and 4 friend came round but were in her room having her own little party

When they left it was 4am and about 7 people were still round with 2 of them passed out and 4 of them were leaving and the rest going to bed and i was still so drunk and i walked in my sisters room and she was drunk as well and she started laughing and jumping on me then as im about to fall asleep she wakes me up and starts kissing my neck and says that she felt attracted to me (we didnt find out we were related until 4 years ago, long story)

Anyways she said she still felt the same even after finding out and started kissing me and i started kissing her back and only have flashbacks but i know what we did and we went further and ended up doing it and now we have barely spoken to eachother since. I cant tell my parents or anyone else so dont know what to do?