[Ennui.]

I like the idea of looking forward to your children's faces when they open their presents! Maybe you can also try to find joy in the little things like Christmas music or some of the old traditional Christmas movies.
Honestly I haven't had the Christmas spirit for the last two years since my niece moved to Florida, so I don't see her around Christmas. We mail her gifts but it's not the same as watching her open them up. It's also just been a rough year for me mentally. I'm trying to look forward to my niece sending me a message with how she likes her gifts from me.
Your feelings are super valid though, and it's understandable that you are feeling this way. Don't invalidate your feelings, but also find joy in some of the small things like I mentioned. Maybe even make some Christmas cookies or another dessert to have a little fun.