Thanks all for your replies. Clinton, I'd considered the carpal-tunnel aspect, 'cuz I really 'break' my wrist when playing - but this event didn't isolate at that spot. I have been slowly modifying my playing in order to forestall any carpal tunnel issues. I know what you mean about those long killer tunes - I get "creatively selective" about my drumming when tiredness sets in during those times. This was different.
Guest, John and Mark - thanks. I assumed this was a circulatory issue. Let's hope it was a "positional impairment of circulation," rather than anything more ominous, like a TIA, although, given family history, that wouldn't be too surprising.
I will visit my doctor, and perhaps explore a consult with a physical medicine specialist. Do you know Mark, if there is a different designation for such in Canada? We have quite a few sports medicine docs here in Calgary, (How many Calgarians does it take to change a light bulb? Lots. One to change the lightbulb and the rest to talk about how great the 1988 Olympics were:)and I know a few occupational therapists, so can access help that way too. I'll post follow up as I learn anything.
Again, I appreciate your input.