Need information from people please

So me and my boyfriend had unprotected sex Sunday. It’s not the first time we had unprotected sex because he would pull out then jerk himself to make him cum and never let the cum touch my stomach or that area. We had unprotected sex Sunday and the next day at night, I started to feel sick like my stomach was hurting so bad. And today it still hurts but not as bad. I don’t know what could’ve cause it because I also take medicine everyday. Could it be my medicine affecting me or another cause from sex?