Sinus Tract Hard Palate, Sinusitis, Abscessed Tooth

Have been dealing w nasal congestion, post nasal drainage on R side. Developed a sinus tract to hard palate which was thought to be caused from abscessed tooth. After 3 unsuccessful root canals I had tooth #2 pulled. Thought that would clear up infection (sinus symptoms, fever, feeling unwell) but no. I'm being sent to another ENT and doc is suspecting a fungal infection, weird bacterial infection and/or infected salivary gland. Has anyone else been down this path or have any advice? PS never had nasal endoscopy.