Thanks, everybody, for your kind comments and anecdotes. I am on the mend, but with fatigue and bronchitis. Also, complete and total loss of sense of smell, even though my nasal passages seem clear now. You could put a full cat box in front of me and I wouldn't even know it.
I had a few minutes' chat with the doctor at urgent care - have gotten to know him a bit, as my late husband and I had gone to that UC for years. I think he is a former military medic. Anyway, in response to my questions, he opined that (so far) COVID shots do not seem very effective at preventing COVID, while the flu shot, while its effectiveness varies from year to year, is worth getting. This doctor sees hundreds of patients a year; these are just his opinions. We didn't have time to get into scientific basis, etc., although I sensed he would've liked to discuss it. Sometimes I think it must get boring for a physician, who is after all a scientist, never to get to talk science except at medical conferences or whatever.
He prescribed amoxicillin just in case I get a follow-on bacterial infection in sinus or chest, but counseled against taking it unless symptoms warrant (increased fever, pain etc).