I like to be on top of the world, as most of us do, but I haven't done very well in the past when I sink into "maintenance mode" rather than aspirational mode. What I learned from my last stumble is that I AM MY OWN WORST ENEMY.
If your kids are old enough, talk to them about how they would like to do Christmas within the schedule you and the other parent have determined. Over time, it does get better. But while things are fresh and hard, make sure you take care of yourself first.