ok.

for the first time, the issue has resolved. and, of course the moment the words are typed....

solution: fresh air. & maybe a little aspirin, too.

i was expecting the aspirin to work within an hour, and then expecting to need to take more a few hours later. i can't isolate a single variable, but it may be the case that it takes closer to two hours to work and lasts for a good twelve hours - or at least does in the presence of fresh air. i dunno. i'm winging it...