Hurts to pee and theres blood...pregnant?

My boyfriend and I have been together for a while now. We are always very safe and careful when it comes to sex. But a few days ago we had sex while I was on my period because I was very light. It ended a day and a half later. But when we had sex he came inside because we had always been told you can get pregnant while on a period (which the day after we found out wasnt true). Now its been a few days but my vagina has started hurting and cramping. And when I pee it hurts really bad and blood comes out. Is this just a urinary tract infection or a sign that I'm pregnant or both...??? :/