We are trying to have a baby, but I got my period and it was heavy, I am bleeding, vulva is burning

Ok, So me and me boyfriend has been trying to have a baby for the last 2 3 weeks. Hes nutted in me like at least once everyday since we started. I ended up taking a test and it said negative even though it was probably to early But the same day i took the test i got my period, it hasn't really been very heavy but its def There. My first daughter i got one last period then they stopped.. I don't really think i am pregnant though. But we just had sex (Yes i am still bleeding some) and it hurt. Like my vagina and my right bottom side of my belly.. Anyone have any idea what it could be??? Please help me!! I plan on going to the emergency room tomorrow i just want some ideas of what it could be..