Ugh...that anticipatory anxiety...I know it well. :/
Try envisioning only good things about
your trip...from the driving to the actual visit, and finally, the return. Keep positive and reassuring mantras in your thoughts.
I am sure that everything will be fine at your home while you are gone. Have you had previous plumbing issues that have caused leaking/flooding? If not, then you really have no reason to turn your water off...but if doing so crosses one of your concerns off the list...then it may be worth it, just for overall peace of mind.
Best to you. You've got this! I hope it is much easier than you expected.
"Courage is not the abscence of fear, it is feeling afraid and doing it anyway!"
"Worrying does not empty tomorrow of its troubles...it empties today of its strength."
Corrie Ten Boom
Panic Syndrome recovery due to CBT