Recently learned that babies have this issue too 😅

In my early 20's I worked a 10-16 hours a day job, 7 days per week. While also attending university. My job allowed me to study, do homework, etc while working. It also wasn't very physically demanding and paid super well. When I'd get home however, more often then not, I would be exhausted but just couldn't fall asleep. I think I figured out that on average I was getting maybe 12 hours of sleep a week. I started taking stuff to help me fall asleep, and it helped, but left me feeling groggy the next day. So I stopped. Eventually, I quit that job and started doing something with a bit more physical activity with way less hours per week. I started sleeping like a baby most nights after that. I missed the paychecks from the other job, but sleep was way more valuable I guess. Looking back 25 years later and I would agree with my younger self, a good nights sleep is worth your body weight in gold.

Yes, on occasion. It's called Overtired/Overfatigue, and if it becomes a pattern it can lead to major health problems over time.

Whenever I experience it I find reading a book helps to make me tired again. Just be careful you don't mess up your sleep schedule, it can take quite a while to readjust.

It sounds a bit silly, but I have been there a lot. For me there was thoughts left over from an unfinished day that would keep me up. It took me years to figure out what the underlying issue was. Insomnia sucks.