Okay So My Boyfriend And I Just Had Sex Last

Okay so my boyfriend and I just had sex last friday and I was on my period, but it was supposed to stop that day (Im on birth control but stopped taking it monday because I'm all out right now) and sunday morning I started to get this discharge with some blood and a nasty smell and it tingles down there anytime I pee. I was thinking I have an STI or something. This is the first time this has happened.