I woke up at 7pm today. Tomorrow I'll probably get up at 9pm. Around this time next week, I'll be waking up at 7am.

This is normal for me. I have a rare-ish circadian rhythm disorder known as #Non24. My sleep cycle doesn't track with the sun. It's not at all rare amongst people who are blind, but it's rare amongst sighted people.

I also suspect it's actually more common than believed & there are people out there reputed to be lazy, immature, or erratic when they just can't sleep normally.