Is it the birth control pill?

Hey guys. So last night I had sex with my bf, and by the end of it i started bleeding a bit. And then it felt like I was losing so much blood because my head was turning and I was blacking out. I’ve experienced blacking out multiple times usually when I’m on my period, but it’ll only took me awhile for it to go away, but last night it lasted for so long, I’ve never experienced anything like it. I was wondering if it is because of the pill? Does anyone experience this too?