Passed out during sex!?

So I was on my period and I wanted to have sex and my boyfriend was like not in your vagina (which I was fine with) So we I gave him oral sex and we were about to do anal. He stuck his dick into my anus and it was painful. I moved forward so he wasn't inside me anymore. All of a sudden my body felt uncomfortable and I got dizzy, I started feeling really hot and began to sweat. I quickly couldn't stand anymore. My boyfriend stopped me from falling and sat me down (that part I didn't remember him doing). So should I be concerned? Was it an orgasm? Nothing like this has ever happened before, but let me know what you guys think.