I guess. This is a good answer, it did made me recontextualize.

Maybe it was always that much obvious to me that what should have been a good night of sleep had no, or maybe even a negative, effect on my wellbeing, and therefore something must be wrong during the sleep.

But if the effects are a bit more muted and accumulate more gradually, and you've never heard much about sleep apnea, you might not directly attribute it to the sleep itself.