The point where you just can't get comfortable.
Where you toss and turn all night but wake up each time because it's such an effort to get the beached whale to actually turn all the way over.
The point where your mind will not slow down and stop for the night.
Where all of a sudden you can now remember all the things you forgot on your list.
I couldn't get to sleep last night, then I woke up every hour and even read a chapter in my book at 3am.