I think this is very common and occasionally experienced by most people, including myself. Typically when you're on the border between being awake and falling asleep.

>I also sometimes get this weird perceptual thing where objects look huge, again, normally while in a dark room.

Haven't experienced this one, but perceptual distortions in a dark environment shouldn't be a concern, I think. I definitely get thrown off sometimes. It's natural, since your brain is constantly trying to predict what should be there, and ambiguous signals due to limited light can throw a wrench into that, especially if you're not habituated to the light conditions.

>I've also had odd sensations that accompany these perceptual changes.

Could there be a nocebo effect? After learning about seizure auras, it's possible that when these things happen, you might enter a brief positive feedback loop where aura-like things could psychogenically manifest. Was this also the case before you learned about such things?