As project managers, we're programmed to worry about everything.

Is some new technology going to be stable enough to deploy?  We have a backup plan to use another technology and a mitigation plan to test the heck out of it early and often.

Are we going to meet the date?  We have a list of what to delay for a while or drop altogether and a monitoring plan so we know when we're in danger.

Is someone on the team playing the lottery regularly?  We ensure that everyone on the team has a backup and as a mitigation plan we buy our own lottery tickets.

We have an answer for everything.  But we still lie awake at night worrying about these things.  And worrying about the things that we've controlled and planned for is counterproductive - it takes our attention and time from things we can actually affect.  It's great for Tums sales but not good for our own health or disposition. (And during the run-up to the holiday season, things can get just as overwhelming on a personal front.)

 I'm as guilty of this as anyone, but at one point I found it to be nearly paralyzing - I was worrying about everything and anything.  As a result, I've taken my mantra from Hagrid (if you're not a Harry Potter fan you can still appreciate the sentiment - and we're rarely dealing with Death Eaters!):

"What's Coming will Come, and We'll Meet It When It Does" 

So when you're having trouble sleeping and your mind keeps gnawing at something, do these three things:

1. Ask yourself if you've already set up a contingency plan and a mitigation plan.   If the answer is no, create these.
2. Repeat your mantra (Hagrid's is a good one, but there are plenty of other expressions of the sentiment) - posting it in a prominent place helps.  I had mine as my screen background for ages and will again if the lesson fades.
3. Move on.  You have better things to do!