Not being able to sleep is a tough spot to be in, and it only gets worse as you get older and not only have more things to worry about, but earlier and earlier times that you have to wake up in the morning. All my life I've been a night owl and have trouble sleeping when I do finally go to bed. I have memories of trying to convince my parents to let me stay up as late as possible, and when that failed, sneaking a book under the covers. You'd think that being tired would be enough to make falling asleep a natural outcome, but this just wasn't always the case.
Eventually I learned that I can usually get past it by counting and I find that I rarely make it to 100 before falling asleep. (My rule is usually that if I get to 100 then I can get out of bed and do something else for a little while.) So clearly my problem is in my head. It's a matter of putting my thoughts to rest, and if I can't, then lulling them out of consciousness.
If only Squeakles could count past 20. And in numerical order, rather than bits and pieces of ordered strings and numbers, such as 1, 2, 3, 4, 5, 3, 17! (The exclamation point there is meant to indicate Squeakles' final shriek as he reaches what he thinks is the final number in the sequence.) Or maybe it doesn't matter if they're actually in order as long as he thinks they are.