See the doctor again. If the problem hasn't gone away, it may not be thrush, You need full testing.
Sometimes a case of thrush is very persistent and requires several rounds of treatment, but this is unusual. Fluconazole (called Diflucan in the US) will usually clear up a case quickly. (The OTC creams are often not that effective.) If fluconazole hasn't worked for you, you may not have thrush. Only a doctor can help you figure out what's going on.
I should mention: in a woman, the onset of her period usually clears up a thrush infection. If you've had a period but still have the problem, it may well not be thrush.
If it IS thrush, you may want to add probiotics to your treatment regimen. Three acidophilus capsules per day for a week could help. But get a proper test done first.