My Name Is Evelyn. I Am 65 Years Old. I

My name is Evelyn. I am 65 years old. I have diabetes, neuropathy, and fibromyalgia. In early November of last year I had my annual flu shot. December 10th I came down with a sudden severe sore throat. By the 12th I also had sinus drainage, a bad cough, weakness and difficulty breathing. I went to urgent care near my home. They said "no strep, low blood oxygen (for which I should get an inhaler) and have a sleep apnea test". The sinus infection, after almost a month, is much better. The breathing is (just) ok. The weakness is still the same. I still have an annoying cough (which happens both day and wakes me up at night). Now my tongue itches a lot, seems slightly swollen, and the surface of the tongue seems cracked and porous. What should I do?