China’s economy started sneezing two weeks ago, and last week US stock markets got sick. How sick?

The Dow Jones industrial average had its worst week in four years as investors ran for the exits wondering just how much growth the US and other countries could muster if the world’s No. 2 economy — that’d be China — devalued its currency in an attempt to get its mojo back.

The sell-off put the Dow in correction mode, down 10 percent.

As folks check their 401(k)s and deal with lower balances in the wake of the selloff, two questions might jump into their heads.

First: “Holy crap! Am I going to have to work, like, another five years to make up for this decline?”

And then: “How come the US economy isn’t doing better as oil prices, which spent 2010-2014 above $80 a barrel, tumble to under $40? Don’t US motorists spend their pump savings at malls and such?”

Let me answer the last two questions first.

Plummeting oil prices have historically been an economic positive — but are not any more. Oil prices are down 58 percent over the last year, but pump prices are down just 23 percent.

The problem this time is that the US today is almost energy-independent, thanks to the fracking boom. That boom has swelled employment in the energy sector to 2 million jobs.

But the cost of producing that fracking gas is higher than it costs Mideast oil countries to produce a gallon of gas’ worth of oil. So as prices fall, US wells close and layoffs follow, thereby offsetting any economic benefit we would have felt from cheap gas.

Now, about that first question.

If you have some years to go before retirement, you might not have to start thinking about sticking around the workforce for another five years.

Stock market corrections are healthy and tend to be rejuvenating.

Sure, it’s not fun, and it will create tension. But it’s just part of the markets. Look, historically it has been far more profitable to be a buyer in a correction.

As the Chinese are fond of saying — “Out of every crisis comes opportunity.”