What's going on?

I've only had one partner, and it is my boyfriend of one year. I take Depo-Provera as my birth control and he pulls out. After I started taking the shot for a few months, sex became very painful and bloody. I haven't had a period since February. I'm not pregnant. I asked the doctor about what could be wrong, which is when I was scanned for STD's and bacteria/yeast infections. I tested positive for a bacteria infection and was treated. I finished the medicine, but it didn't seem to help at all! Can anybody help me figure out what's going on??