I used to get tons of homework in middle school. I would usually start working on it at 10 p.m. and plow through till 3 a.m. Sometimes, I would fall asleep on my desk, then wake up a few hours later to see the few lines of gibberish I wrote before dozing off.
I just feel tired and sleepy after 2:30 a.m. I realized this even more during university breaks. My usual sleeping time would go forward from 10 p.m. to 3 a.m. in a few days but then get stuck around that level. 3 a.m. to 11 a.m. is my ideal snooze time. For various obvious reasons, that's not my sleep schedule today.