Was it assault..?

Ladies,

I know this is not the group to ask this but I don't know where to go. A few years ago I had a boyfriend. One day he was 'in the mood' and was pressuring me to give him head. No matter how many times I told him no he would keep asking me please. He was persistent and I gave it. He got on top of me and did the work himself. He knew I didn't want to. The next day I told him I was upset because I felt that was sexual assault, but He said that I was wrong because I gave him consent. Years have gone by and I still think about this. I was young, only 15 at the time. I don't know what happened or what it was. Can anyone here give me some answers?