Sunday is a great day to do something for yourself.
You could play tourist in your own town.
Go outside and talk to a tree. (Be sure no neighbors are around...)
Take a nap under a weighted blanket.
Drink your coffee with whipped cream on top.
Pull out your Christmas movies and watch a favorite.
Make a list of tiny victories you've had in the past 6 days.
Put a tiny paper umbrella in your tea.
It doesn't matter what it is. Just do something today that is completely for you. Fun. Relaxing. Silly. It doesn't matter.
It's self-care and it's even better if you make it a regular practice.