Your doctor didn't even do a quick culture to send to a lab?
When I told my doctor I had weird discharge down there, he had a nurse collect a sample and send it out. Got results in 5 days saying it was a yeast infection.
Ask your doctor to do it. If he refuses, call around for a doctor who will. Another OB or a family practioner who does this sort of thing.
Could be bv or a yeast infection. Should be checked.