Cocooning is normal after all you've been through. It's not something that you want to get stuck in and have last forever, but it sounds like you just need to pull back in a little and regroup.
Maybe set a date for a week or two from now, something you can commit to that is fun. Promise yourself that you will go do it.
Then give yourself permission to hibernate for a little while. Take a bubble bath. A nap. Just some self-care, even if that means zoning in front of the tv and not thinking about anything for a bit.