Really need some advice

So I haven't told anyone this ( except my ex fiance & my best friend) so about 6 years ago I was staying with my cousins for the weekend like I did most weekends. Well we were very close like brother and sister but were cousins. So we were in his room laying down on the bed watching tv ( everything normal ) well he started getting touchy with me and I thought he was just playing cause we use to play fight. Well things got awkward when he touched my boobs and I was like " what the hell?" I really didn't pay much attention to it and let him ( I know it was wrong I was like 13 ) but then he kissed me and I freaked out. I was fixing to run out the room when he grabbed my hand and told me please don't leave let's talk about it i said okay so he said he was sorry and didn't mean it. So a few minutes later we were laying close and then he started trying to get in my pants and I told him no and then he said please and I said idk... ( remember I was like 13 I really didn't know that much about sex and I was very confused ) anyways I'm not sure how we got to this point but I remember he sticking his penis inside my ass ( anal ) I didn't know what that was at that time. but I do remember telling him no and stop! but he didn't listen so I thought I did something wrong... after he was finished he went to the bathroom and I just laid there crying cause I didn't know what really happened and I was hurting. He told me that it was our little secret. ( i forgot he was like 12 I think but he was a lot bigger then me ) is that rape? UPDATE: I got married about 2 years ago and my hubby wants to do anal we've tried before but I remember what happened and I kinda freaked out and started having a panic attack. my husband asked me what happened and I said nothing don't worry. I don't know if I should tell him or not... What should I do?