Suggest Treatment For Fishy Odor From Vagina After Intercourse

I had a "fishy" odor coming from my vagina after intercourse, went to my doctor and she checked my discharge and assured me that I had NO bacteria but a lot of yeast. She prescribed be a one-dose diflucan. This was 3 wks ago and I had intercourse again and still have an odor, not as bad but it is still there. I am wondering if my yeast infection may not have cleared up all the way or if I was miss-diagnosed and have bacterial vaginosis, I am freaking myself out and not sure if I have to go back to doctor or try an OTC treatment for yeast infection?