bv during pregnancy

I have had this strong vaginal odor that is only noticeable when I go to the bathroom, like a strong iron scent. I was tested for STDs 3 weeks ago that came back negative because I had had a yeast infection. I am 22 weeks. At 7 weeks I was diagnosed with bacterial vaginosis and was given an antibiotic to take 4x daily for 10 days. After that, nothing was ever done. Could it be that my ph balance is off? What can I to solve this?!