What keeps you up at night?
David said that he had thousands of enemies - although he actually just had one main enemy. But the reason it was extra troublesome is because it was his own son! Maybe it is worries about your children that gives you a restless night's sleep.
(by the way... I'm expecting that you've read the Psalm of the Day before you read my comments.)
But David was able to lay down and sleep! Ahhhhh.... wouldn't that be nice?! How did he do that? He trusted in God. He turned his troubles and worries over to the only One who could ultimately sustain him.
Jesus worded it this way in Matthew 6:
Read all of this passage here - Matthew 6:25-34 Don't worry
The Apostle Paul had similar advice.