I'm sorry your having so many problems. According to *****.com, the causes of glossitis include:
Bacterial or viral infections (including oral herpes simplex)
Mechanical irritation or injury from burns, rough edges of teeth or dental appliances, or other trauma
Exposure to irritants such as tobacco, alcohol, hot foods, or spices
Allergic reaction to toothpaste, mouthwash, breath fresheners, dyes in candy, plastic in dentures or retainers
Disorders such as iron deficiency anemia, pernicious anemia and other B vitamin deficiencies, oral lichen planus, erythema multiform, aphthous ulcers, pemphigus vulgaris, syphilis, and others
Occasionally, glossitis can be inherited.
As for the thrush, I had it for 2 1/2 weeks after septoplasty, turbinate reduction, adenoidectomy and tonsilectomy and my ENT put me on Clotrimazole 10 mg Troche. They worked very well. You let them dissolve in your mouth slowly four times a day. You might ask your doctor for another thrush medication.