Meh. Tried writing one under 100 words. And I was reading some Lydia Davis.
She takes a pill when she worries. But then she worries when she has stopped worrying. That is, she worries that she is not the kind of person to worry over important things in her life. In her mind, people who worry are on top of things.
So she doesn't take the pill the next time she worries, only to find that she is weary with her worry.