What Causes Spotting During Urination After Having Sex?

I started my period 2-19 and ended 2-24 i am always normal, no spotting in between periods. My bf and i had sex six days after my period and the 4 days later the following morning i noticed a discharge as if i was going to start my period but nothing, then the following afternoon i went pee and there was light blood in my pee as if i was going to start my period so i put a tampon, its not my period just light spotting and at time its brownish.. Its going on two days... What can this be? Im not on bc my bf pulls out before he ejaculates.