One day you can be riding a bicycle beside the Pacific Ocean, admiring the beautiful purple flowers and laughing with your friends. The next day you can be driving down the interstate in pouring rain, cursing the traffic, with a pounding headache. Then once you arrive at your destination all the children you're working with decide that they must play a role in some kind of karmic retribution for something you did in your past life and they proceed to scream at you, full throttle, until your blood pressure is up, and your face is hot, and you have a mother of a head ache.
Then to make things worse, you're at that middle murky part of your manuscript where everything just seems wrong, and you keep writing because you think if I can just get out of this part, it'll get better. But you just can't get out, because you're stuck in mutant quicksand, and the kids are screaming at you!
Maybe today will be better.