Elusive Shut-Eye

"When I want to go to sleep, I must first get a whole menagerie of voices to shut up.   You wouldn't believe what a racket they make in my room."

                                                                                                                        Karl Kraus

I never have a problem slipping past that line and into deep sleep at the start of night.  I can fall asleep regardless if the lights are on, radio or t.v. playing, windows open or closed, or partner snoring; an ability that makes me an especially good roommate, I think.
No, falling asleep is not my problem; staying asleep, however, is.  Once I wake, it can take some time before I can return to a sleeping state. Occasionally when I have to go to the bathroom, I try to make it quick, keep one eye closed to attempt to fool myself into thinking that I am still sleeping.
This middle-of-the-night time is not always wasted time for me.  My mind wanders; I do ponder life's mysteries in ways that I never do when awake, sometimes I even have a thought or two worth recording.  (It is always fun to read these the next day). Now and again I can make real headway reading my current book... time well spent.
Periodically, though it is totally meaningless meanderings that this brain of mine seems determined to track. The worst is when I start in on the middle-of-the-night worries.  Why must they always be the darkest?  Maybe it has something to do with that old saying that the darkest hour of the soul is three in the morning.  But what is it about daylight that denies these worries their intensity, that flattens those spikes of fear and anxiety, that dials back the thinking to whatever normal is? 
Sadly for me, no matter how much sleep I've missed in the night, as I've said before, I can't nap during the day.  Now hubby is different, he can wake up in the morning sometimes already looking forward to having a nap.