Sex Pain!! HELP!!

I'm 18. My boyfriend and I were having sex and as he was going deeper (usually does and it's fine) it was hurting everytime he went the deepest he could, I took the pain for a little bit but soon I told him to come out because of the pain. That was at about 1am. After that almost immediately my body began to ache. My stomach, butt area and actual vagina was aching extremely bad every time I moved to the point where it kept me up till about 6am. The next morning when I woke up my stomach was hurting under my belly button every time I would flex it. Now there is no pain but I am still worried about what it was. About 2 days later I got my period which I only get about 2-3 times a year. Maybe that has something to do with it?? Anything is appreciated!!!