Woodlock: "Exhausted to the bone but not tired", you put it perfectly for my understanding.

Also at one point I read something about something called "monkey house". It's basically that you keep thinking about falling asleep to the point that you can't fall asleep because of it, it's like monkey sitting on your back. And it's (too) often true for me.

I hope you don't have problems with sleeping anymore though and won't have those in the future!