Must be something going around, alright. I'm just getting over a bout of viral bronchitis (so said the doc) that seemingly started as a cold or sinus infection that kept me off the bike for nearly two weeks...and I dropped out halfway through a club ride just last night.
The achy joints sound like flu but it's not flu season. Anyway, whatever it is can take a lot out of you.
I'm for the time-honored treatments: rest and fluids. Including chicken soup. I have no problem with OTC sinus/pain reliever. I regard echinacea as dubious at best. Actual drugs at least have to be tested for efficacy and safety, whatever the shortcomings of the FDA. "Supplements" like echinacea don't even have to pass that muster.
I also took "a light spin" around the neighborhood when I finally began feeling better. The bronchitis made for considerable fatigue.
Wanted to reply in verse but coudn't rhyme "bronchitis".
Take care.