Should I be feeling this way? TW

When I was 12 my older sister had a boyfriend. I didn't really know him that well but I still went with him and my sister to his house. When my sister fell asleep he had asked me if I ever had sex and I had said no. He had then asked me if I wanted to and I thought he was joking so I said yes. So then he started making moves on me and I didn't know what to do so I just let it happen so its not like it was rape so I don't know why when I think about it I cry and I get so sad. Should I be feeling this way or am I just overreacting?