"Where are all the customers?" asks an internal Walmart email published by Bloomberg last week. "And where's their money?" Another email states "In case you haven't seen a sales report these days, February [month to date] sales are a total disaster . . . the worst start to a month I have seen in my ~7 years with the company."

Brad Plumer notes that Walmart sales are often a bellwether for the rest of the economy. Should we be freaking out?

I'm all for a modified limited freakout. To be sure, Walmart is likely to be disproportionately affected by the changes we've recently made in government policy. Ending the payroll tax holiday probably cut substantially into the disposable income of Walmart's "value oriented" customers. And because the debt ceiling deal was an eleventh-hour negotiation, the IRS couldn't process tax returns as fast. Normally, they'd be starting to roll out around now, ballooning Walmart's sales with once-a-year investments in stuff like furniture and electronics.

So there's reason to hope that this effect is 1) temporary and 2) somewhat Walmart-specific. So why freak out at all?

Because of fourth quarter GDP, which was terrible. Yes, it was an initial number that will eventually be adjusted, presumably upwards. But it's still really bad, and the best we're hoping for in a revision is "lackluster". Consumer confidence isn't so hot either.

So while I wouldn't sell the stocks and hide under the bed with your canned goods and rifles, I think there's reason for concern. If Walmart sales don't recover in the next few months, we may be in for a bumpy ride.