What Was It?

I’m not sure what happened to me. I was young, i didn’t know what he was doing. I’ve never told anybody. I recently started thinking about it a lot I think it because I’m 16 now. I just wanna know what it was.
I was five and didn’t have any friends. He was the same age I think. He was in my class and my neighbour. He asked me to go into the toilet with him. I said no and he replied by saying I won’t be your friend then, and a vey young, naive and lonely me went with him. While in the toilet, he told me it was a secret and i couldn’t tell anyone. He started to touch me and I didn’t know it at the time but he did oral sex on me. I was so uncomfortable, I didn’t want to do it! I just remember wanting a teacher to walk in and stop it, but no one ever did. I think more stuff happened but i blocked most of it out. I remember seeing his private parts but I can’t remember what he did with them. I didn’t tell anybody I just pulled up my tights and walked away. We never spoke of it again. As I grew up I started to wonder if he knew what he was doing, if he’d seen it at home and was copying or something. Was it done to him? Did he go further than oral?
I feel disgusted and sick by what he did. Children and supposed to be innocent, I wasn’t. I don’t know whether it was rape because its not like he held me down? Can it even be sexual assault because of his age? Or am I just over reacting?
I am self conscious of my body, I am shy and I don’t like contact from anyone. I think I’m like this because of that one event. I know i can get passed it. So what was it. Rape? Sexual assault? Two kids being weird??? I’m not sure.