Only 11 days until mine as well! I'm finding getting on the treadmill in the morning is clearing my head, as well as, just doing any little thing I can to feel ready no matter how small a task it seems.
Eat properly. Drink lots of water and stay hydrated. Get proper sleep.
Make a list of everything you need to do and when you need to do it by to keep yourself organized! Also as hard as it is to not stress, just remember that even if something goes wrong or is out of place no one will know except you and your partner. So it’s really not a big deal and people will have a great time regardless!