Drunk and no consent

This is a serious post. I was at a club with my friend and was seriously drunk (I was dancing that's how drunk I was lol). This guy came up to me and forced himself on me. I turned my head but he pretty much had me in a head lock. He started touching my ass and my boobs. My friend was too drunk to help and I was too drunk to get this fucker off me. The problem is I have a boyfriend. And he's warned me not to get drunk because this shit happens sometimes. I'm really afraid to tell him because I think he'll be disappointed in me and think I deserve it... how should I tell him?