It is something that is most likely to happen right after something big has ended. Maybe you have lost a job, broken up with a romantic partner, or finished and delivered a big project. Maybe two or three things like this happened almost at the same time. The abrupt change has an obvious effect on your schedule. One day you were rushing to keep up and meet obligations and deadlines; the next, you had the unmistakable feeling of time on your hands.
And it does not stop there. With more time at your disposal, you catch up on other tasks that had been lagging or neglected in recent weeks or months. If you continue to work diligently, those too are soon finished, delivered, struck off your list. After a relatively short period of this, life can start to feel positively empty. It only seems emptier day by day as your backlog or to-do list gets shorter and shorter. This is an effect I have come to refer to as the cascade of emptiness.
Though it is likely to feel like a problem, this dynamic is actually one of the great moments of opportunity.