Hurts at the end of peeing?

So my girlfriend and I were both virgins the first time we had sex, and about two weeks afterwards I started to get a burning feeling at the end of peeing. I didn’t know if this was from too much masturbation (or too hard) or what. We had sex today and we noticed bleeding afterwards, which could just be my period as I get it around this time (we’ll see if that’s what it is tomorrow).