Strongly recommend a culture. If your sinus condition is caused by C krusei - Diflucan will do nothing. In fact, it can convert harmless albicans to krusei. I'd snort (and have) Nystatin before Diflucan.
It could be any number of molds, or a combination (cultures found five molds in my sinuses).
Proper treatment is essential.
Adding a drop of baby shampoo to whatever spray you concoct should help. Contains zwitterionic (a surfactant) which will help break up biofilm, allowing better penetration of solution ingredients.