Thanks for all the well wishes.
Short update. Felt much better by Friday, and by Saturday I had ditched the crutch and was handling stairs and a 2 mile walk.
Then came my COVID booster, previously scheduled for Saturday late afternoon. I had no adverse reaction to the first two shots, so what the heck.
By Sunday morning every bump, bruise and muscle pull had been exaggerated to the point of torture. Lost the whole day lying on the couch mindlessly watching football.
Then it passed. Thinking a light round on the trainer tonight is in order.