Go back to your doctor and get a swab done from your mouth to be sent to the laboratory for analysis.
It is highly likely it is a fungal problem, but sometimes furry tongues can be from gastric issues.
Sometimes one course of antifungals is not enough to treat the problem. So you may need a few courses of antifungals. There are also antifungal capsules that you swallow with water. But the oral gels are better for the mouth issue.
Eat live natural yogurt and cut down on sugar foods and fizzy drinks and squashes.
Make an appointment to see your doctor.
Did you find any solution ? I have a hairy white tongue at back of my tongue , and i feel as you sand in my mouth it make my breath bad really need help