Over a period of three turbulent days leading up to and immediately after Standard and Poor's downgrade of the country's sovereign debt rating, U.S. stocks plunged with a ferocity and velocity not seen the darkest days of the economic collapse of 2008.

During this stomach-turning three-day span, the Dow Jones Industrial average lost 9.13% of its value while the much broader Standard & Poor's 500 Index, which plunged 6.7% on Monday alone, was off 18% from its April 29 peak.

The sell-off on Monday followed the surprise announcement by S&P’s ratings analysts that the agency was lowering America’s vaunted AAA credit rating to AA+ with a negative watch, meaning further downgrades were not out of the question.

On Tuesday, the Dow rallied to close up more than 400 points after some back-and-forth trading throughout the day, but most market strategists and economists were warning that the U.S. economy is in serious danger of falling back into a recession and U.S. and global equities appear primed for even more volatility.

Not surprisingly, financial advisors have been touchstones for this latest crisis with clients -- many still shell-shocked from the 2008 market implosion -- wondering if they are about to experience their own version of “Groundhog Day.”

Denis Fatovic, an advisor with Financial Network Investment Corp., in Teaneck, N.J., told On Wall Street, “Yesterday, the phones were ringing off the hook. People wanted explanations and answers. Some were in a panic and felt they had to sell something out of their portfolios.”

He said, “I told people that they needed to separate emotion from real practical investment issues and that I could help with those issues, but not with the emotions.”

As for explanations, Fatovic said he told people that “markets may be on thin ice, but that doesn’t mean another recession is imminent.”  He urged people “not to sell into a fire sale, and to make wise decisions,” that those with long-term investment goals should “stay put,” and that for others, it could be a “buying opportunity” to have markets so low.

Starlette Vance, a financial advisor at The People's Bank in Ripley Miss., said, "I have some clients calling me, but most of the ones who can't stomach this kind of thing already left me in 2008.  I tell those who call not to be afraid. It's just a temporary thing and the government is fixing it."

"I do have some clients who are nearing retirement, and I tell them I have got the medicine for them -- annuities -- but some of them aren't ready to take it," she added.

Meanwhile, Rhonda Arnett, a senior financial advisor with PrimeVest in Tacoma, Wash., said, "This week has been very unsettling, and investors are genuinely concerned, but I'm not getting deluged with calls from clients. The ones who call are the ones who usually call me whenever there's some bad financial news on the TV."

Arnett added that, “a majority of my clients have already addressed their short, intermediate and long-tem liquidity needs, so they're able to sit this out. In most cases we don't need to react. But I am trying to reach out to all my clients."

"I'm telling people that it's a good time to buy, and in fact, I'm doing that with my own funds -- buying great, good-quality large cap U.S. and international companies, oriented towards those that pay dividends," she said.

Not everyone is ready to call the current moment a buy opportunity, though. Kevin McDermott, a senior financial advisor at Citadel Federal Credit Union in Downingtown, PA, says he’s telling his clients to “sit tight.”  He said, “I’ve had some clients buy assets, but I’m not actively going out and saying, ‘This is a buying opportunity.”

With plenty of issues still unresolved (Is the U.S. economy headed back into recession? Will European central banks manage to act decisively to prop up the debt-burdened member nations like Greece, Italy, Spain and Portugal? Will Congress manage to seriously attack the country’s growing national debt and avoid further ratings downgrades?), it’s hard to know whether now is a time to run outside and shop for bargains or to stay hunkered down in the storm cellar.

What does seem clear is that clients need a lot of handholding and advice to keep them from responding emotionally to a situation that requires clear thinking deliberate action.

For more on the debt rating downgrade fallout, take a gander at Financial Planning's special report package for details, insight and advice from some of the financial planning industry's foremost experts.