Yes, there's a natural ebb and flow of feelings and being. When things are really bad I try to think of one of the end scenes in Harry Potter and the Sorcerer's Stone when they were caught in the "Devil's Snare" plant and had to relax and fall through it rather than fight against it. Do something anyway, no matter how bad you feel, to pass the time and distract you until you can feel better. I always figure if things are so bad, might as well do things I hate to do (cleaning and other housework) since I feel so bad anyway. Usually though I don't feel that bad :-) so I manage to find something more interesting to do that I prefer. Even feeling bad you'll find there are things you prefer doing and "preference" is a positive thing.