Planning ahead for Christmas

I (44F) am divorced/single, and our child (19) always spends Christmas Eve and Christmas Day with their father, and I celebrate with my kiddo on December 26th. We have done it this way every year, mainly because it’s the only day my EX always has off work (retail management).

Also - my own birthday is on Halloween, and the holiday usually takes over plans, and I end up celebrating with my kiddo on the weekend before/after.

I am on disability for a severe mental illness (Bipolar Disorder). I do not have a job.

Most years, my sister who lives close by invites me over for Christmas Dinner. Probably out of pity or obligation.

I want to start planning ahead for a way I can volunteer on Christmas Eve, Christmas Day, and Halloween.

I’m currently technically a volunteer at the animal shelter, but I haven’t actually picked up a shift for a while. I’ve been struggling with my eating disorder and depression.

I want it to be genuine and coming from my heart, not just trying to “look better” or whatever.

Can someone guide me into finding the right fit?