I've had similar experiences, especially when sleepy. The interesting thing is that, at least in my case, it's often difficult to remember the subjective experience of it--once the correction kicks in, the earlier rationalizations seem to be subject to the same fading effect that makes dreams tough to remember, especially when I haven't acted on the original confusion (as you did by turning on the lights).
Also, this is why it's probably reasonable for all of us to be confident that our left arms are not, in fact, paralyzed--because we have evidence of the anti-confabulation systems in our brain working as intended (if a bit slow to catch up, on occasion).
Followup to: The Strangest Thing An AI Could Tell You
Brain damage patients with anosognosia are incapable of considering, noticing, admitting, or realizing even after being argued with, that their left arm, left leg, or left side of the body, is paralyzed. Again I'll quote Yvain's summary:
A brief search didn't turn up a base-rate frequency in the population for left-arm paralysis with anosognosia, but let's say the base rate is 1 in 10,000,000 individuals (so around 670 individuals worldwide).
Supposing this to be the prior, what is your estimated probability that your left arm is currently paralyzed?
Added: This interests me because it seems to be a special case of the same general issue discussed in The Modesty Argument and Robin's reply Sleepy Fools - when pathological minds roughly similar to yours update based on fabricated evidence to conclude they are not pathological, under what circumstances can you update on different-seeming evidence to conclude that you are not pathological?