I have the same problem. I have White tongue and bumps in the back of my tongue. I went to the Dr. he gave me the mouth wash and went back and gave me pills, with no result.
I went to the oral surgeon and he told me that its nothing to worry about. I showed him the roof of my mouth, which is cloudy looking and he told me to stop smoking and drinking. He also told me that my white tongue can be from anxiety too, which is weird because its been almost a year.
You may want to try a local dental school and see if an oral pathologist will look at it. It does sound like thrush to me and sometimes it takes a good strong dose of meds to take care of it.
I have a white coated tongue with red spots on the back and linda the middle i looked in my mouth and it is greenish or yellowish i dont know what it is but i supposely had a urethea infection and one day i think i woke up with anxeity disorder i dont know whats up with my mouth but im scared please help