<human>: Uhg okay so this just happened and I'm tipsy so excuse me for not making sense but I'm really upset and I'm not sure if I should be. 1 year and a half relationship (FYI MODS). Basically my boyfriend and I have a very nice, kind and gentle relationship except for when it comes to sex, then it's BDSM-ish (I submissive, he dominant).

Anyways, we were drinking with friends and we were talking about BDSM kinda of and he was teasing me and slapped me on the back (really hard, made a loud noise). Thing is, I don't think he meant to hit me that hard because usually I'm okay if it's a little pat, and I also think the alcohol was taking over because he is extremely gentle- but also it's never been on the back and I've had physically abusive ex's and he knows it (abuse outside of bedroom play) upsets me.

Anyways, I brushed it off but since I have a chronic pain disorder he basically triggered a fair up and I started to feel extreme pain and frustration since I was slightly more drunk than I am now. Then my other friend started to get defensive with me (over something else) and everyone was talking and I just couldn't handle the pain + too much noise + someone yelling at me so I stood up and shouted "okay! I'm leaving!" (yeah I know, kind of immature)

Now I'm sitting in my boyfriend's room because I can't drive anywhere and I have no friends (other than the ones here tonight) in the area since I live a few cities over.

Thing is, I'm not sure what I'm really upset about. I'm not sure if I have a right to be upset?? If you know what I mean. Don't know where to go from here, but emotions are high and I am not feeling okay at all.

Can you succinctly summarize the text in 1-3 sentences?
<bot>: Boyfriend hit me, didn't mean to, still am upset, have no idea what to think. It's better if you read the whole thing to get a better understanding, can't really sum it up.