Investors fear hard-won gains could vanish again

“I’m nervous. I’d like to take everything out and put it in the mattress, but you can’t do that,’’ said Sherman, 44, while loading bags into her car outside a Plymouth grocery store.

Matt Liptak, a corporate recruiter from Dedham, also has been shaken by the stock market’s plunge on Thursday - a more than 500-point drop in the Dow Jones industrial average - which was followed by jittery trading yesterday. In 2009, Liptak had to pull $15,000 out of a 401(k) plan after being laid off. He has steadily been replenishing his savings since then, a march toward economic stability that suddenly seems to have hit a major roadblock.

“It is worrisome,’’ he said. “I built up my 401(k) quite a lot in the last couple of years, [and now] who knows what could happen to it?’’

So far, however, Liptak, 41, isn’t tempted to withdraw his money or make drastic changes in his portfolio, a cautious approach that most financial advisers endorse.

Still, for ordinary investors - those whose involvement in the complex world of finance involves thousands, not millions, of dollars - there was no escaping the “Will I have to start all over again?’’ feeling this week. The recent string of down days seems especially cruel because it began just as investors had nearly recouped the massive losses they suffered during the market crash that began in late 2008.

The Dow, which peaked above 14,000 four years ago, lost more than half its value by March 2009, leaving many individual investors afraid to open their 401(k) statements. For those who needed to tap into their funds, it was a particularly devastating period.

And while the uphill climb has had its bumpy moments, investors who stayed the course received a payoff - this spring the Dow was closing in on the 13,000 mark. Today, with the average well below 12,000 and talk of an economic recovery turning into speculation about another recession, the dark days of a few years ago seem uncomfortably close.