Do you have an actual fungal infection of the sinuses? Or, are the mast cells in your sinuses being irritated by chemicals being dumped into your blood stream by a candida overgrowth in your intestines? It is fairly routine for ENTs to pull actual fungus balls out of a patient's sinuses. I believe the Mayo Clinic released a study a number of years ago suggesting that fungus physically present in the sinuses was the root cause for many cases of chronic sinusitis. If your case is one where there is fungus physically present in sinuses, I tend to doubt that products taken to control candida in the intestines will give you much, if any, relief.
So, instead of merely dosing you with anti-botics, perhaps a culture could be taken from your sinuses. Wouldn't it be refreshing, even enlightening, to actually know whether a fungus or a bacteria is causing your long term misery? Because if a fungus is the cause of your sinusitis, not only are you wasting your precious dollars on anti-biotics, you may be seriously undermining your health.