After weeks of steep market declines, you may feel you've had enough, that you want your hard-earned money during these uncertain times with you, under quarantine. And who could blame you?

Headlines warn us that we're careening toward a global financial crisis uglier than 2008, and the stock market has seen some of its worst days in history recently, as a new virus rips across the world and paralyzes economies. The last couple of months have been brutal for investors, particularly those nearing retirement or another deadline like sending a child to college or coming up with a down-payment on a house.

Let's say you had a $1 million portfolio, split between U.S. stocks (70%) and bonds (30%), on Jan. 1 of this year, at which point news of the coronavirus was just starting to trickle out of China. By Monday, March 23, your savings would be down to about $780,000.

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Worse yet, we're told there's no end in sight for this global health crisis.

Despite the unprecedented times, though, some things never change: If investors can't tolerate the losses, they'll also miss out on the gains. "Pain is a sign you're investing well," said Allan Roth, founder of financial advisory firm Wealth Logic in Colorado Springs, Colorado.

Let's return to that $1 million portfolio beaten down to $780,000.

If you'd capitulated – in investing terms, cut your losses and moved to cash – on Monday, when it hit that low, you'd have missed the massive gains the market saw the very next day, on Tuesday, March 24. That day, the Dow Jones Industrial Average had its biggest one-day spike since 1933.

And that portfolio, as a result, was back up to more than $830,000. (These calculations were provided to CNBC by Morningstar.)