I recently wrote about Mark Jung's presentation about the phases of a start-up. While not technically a part of the '5 phases' and referring more to an individual (i.e. the founder), Mark also talked about a 'Dark Phase'.
During the Dark Phase you ask yourself if you still believe in yourself and the company? What does failure mean? How are you coping with failure? You wonder how the carnage could have been prevented? (I love that Mark used the word carnage). You reflect on the amount of responsibility or blame you should take? What do you do now?
There are no answers. They are tests.
I think 'Dark Phase' is a great term. It's comforting. Everyone has setbacks and failures. Everyone hits entire periods of darkness. Knowing that it's normal and expected helps. It's how you respond that matters.