You certainly are not the only one, I have seen threads from many burnt out caregivers here.
I'm sorry Christmas is so hard for you and that everyone expects you to cater for them.
I don't have advice, just sending care and hugs.

You're a caregiver, burnt out or not, you're amazing, people the world over sacrifice their own selves to care and I have deep respect for them (you).This task has not been asked of me yet, so I don't know what it's like.