When I am having a bad day, I feel grateful just being able to get out of bed. I have some long knit dresses that you just throw over your head. They are so comfortable. I even use them as night clothes, then you don't have to worry about getting dressed in the morning.
So you go a day or two without washing your face, combing your hair, or taking a bath. The world is not coming to an end. I can remember the days when we only took a bath and shampooed our hair once a week.
We cannot be on top of everything all the time. Give yourself permission to take a day or two to just sit and regroup. So many of us beat ourselves up by thinking that we "should".