Pain after sex

Hello!

I rarely post on here, but I was seeing if anyone could give me advice.

I recently had sex with my s/o we rarely have sex, because it ends up hurting me a lot. Well, anywho, we did and we ended up ending early, because of the pain. I went to shower and as I was washing up I realized there were two quarter size knots on the opening on my vagina. Fast forward about 2 hours and now I'm bleeding a lot, he has triggered my periods before, but.. I haven't had my period in a year due to an IUD I got 3 years ago.

Also, does anyone have any recommendations with preventing pain during sex?

😬😬