Bleeding after sex

Kortney • Don`t go alone, it`s dangerous.
I just went to the doctor but she's not a very good one I just had to go with it until I get transferred. She told me I had a bacterial infection but when she gave me my paper work everything was fine and dandy. All normal. They did blood work. Everything. I've looked up online about it and all I saw was pregnancy, STD, and bacteria. Took a pregnancy test at the doctor, negative. I've also had my period since then. They checked my blood and everything. No STD.  Also my partner and I haven't had sex with other people in 2 years (before you start asking me how I'm sure, we go everywhere together. The only time we are apart is when he's using the bathroom). And now apparently I have no bacteria. I had no idea what this could be?