Meaning behind this quote?

"Now the standard cure for one who is sunk is to consider those in actual destitution or physical suffering—this is an all-weather beatitude for gloom in general and fairly salutary day-time advice for everyone. But at three o’clock in the morning, a forgotten package has the same tragic importance as a death sentence, and the cure doesn’t work—and in a real dark night of the soul it is always three o’clock in the morning, day after day. At that hour the tendency is to refuse to face things as long as possible by retiring into an infantile dream - but one is continually startled out of this by various contacts with the world. " - F. Scott Fitzgerald. I really like the quote but I want to know what it means. Help?