Sometimes, especially when one of the kids isn't feeling well, I wake up in the middle of the night and just cannot go back to sleep until I go upstairs and feel each of them to make sure they are still breathing. Maybe it's a mom thing, I don't know. But when you can't hear anything on the monitor or physically see them, you just have to know.
To save my sanity and help myself go back to sleep, I've started quoting Psalm 23 but putting each child's name wherever there is a "my" or "me". It really helps to remember that The LORD is their Shepherd and that because of that, they shall not want. That they can fear no evil, for HE is with them. And, I know this isn't in Psalm 23, but elsewhere in the Psalms it says that He who watches over Israel neither sleeps nor slumbers. So even when I have to go to sleep and can no longer watch over them like I'd like, He doesn't miss a thing. He is up watching my kids while I sleep. How cool is that??