Bleeding during sex ??

My boyfriend and are are sexually active but the last few times we have had sex I have bled during sex. It’s not like spotting, it is a decent amount of blood. I just went to get checked and I was negative for chlamydia and gonorrhea which was a big concern. I did come back with a UTI so maybe thats it? It’s really scaring me and interfering with my sex life.. Anyone have the same problem or any clue what is going on? (I brought it up when I went to get checked and they didn’t say anything about it)