New York (CNN Business) The US stock market sank deeper into the red following sluggish economic reports on Monday and bad news from a couple of blue chip giants.

The Dow fell 508 points, or 2.1%. The S&P 500 lost 2.1% and retreated to its lowest level of the year. And the Nasdaq joined the Dow & S&P 500 in negative territory for 2018. All three indexes have plunged nearly 8% so far this December.

And the Russell 2000 index of small-cap stocks tumbled into a bear market, marking a decline of more than 20% from the record highs notched in late August.

A weaker reading from the New York Federal Reserve about manufacturing in the Empire State and a drop in confidence from the nation's homebuilders weighed on the markets.

"Investors are zeroing in on this idea of slower growth for 2019," said Michael Arone, chief investment strategist at State Street Global Advisors. "More people are worried about a recession in late 2019 or 2020."

Bruce McCain, chief investment strategist at Key Private Bank, said Wall Street might be overreacting to the economic headlines.

"Most of the economic signs point to slowing but not radical slowing. We think the market is overestimating how bad it will be," said McCain.

The political noise in Washington isn't helping either. President Donald Trump, in a tweet Monday morning, repeated his criticism of the Federal Reserve for its recent rate hikes. The Fed meets Wednesday and is widely expected to raise rates again.

But Trump tweeted that "it is incredible that with a very strong dollar and virtually no inflation, the outside world blowing up around us, Paris is burning and China way down, the Fed is even considering yet another interest rate hike. Take the Victory!"

The Fed is supposed to be politically independent. Any evidence that it might be swayed by attacks from Trump could unnerve the markets.

"If the Fed doesn't raise rates it will look like it's succumbing to the bullying of Trump's tweets," Arone said.

But Nancy Perez, managing director at Boston Private, said the Fed is likely to slow down its pace of rate hikes in 2019 simply because the economy is slowing, not because of pressure from Trump.

Perez added that the recent market turmoil is justified because investors are readjusting to this fact.

"We have been getting a bump in profit margins due to lower taxes but the earnings growth itself is not sustainable," Perez said. "Projections will come down and volatility will continue."

J&J, UnitedHealth and Goldman Sachs were the day's big movers

Investors had more to worry about than the economy and politics though.

The Dow's losses were led by a continued drop in healthcare and consumer products giant Johnson & Johnson.

J&J ( JNJ ) plunged 10% Friday following a bombshell report by Reuters alleging that J&J was aware its trademark baby powder contained asbestos . J&J has said the Reuters report is factually incorrect. But the stock still fell another 3% Monday.

Dow component UnitedHealth ( UNH ) fell nearly 3% after a federal judge in Texas ruled late Friday that the individual mandate of the Affordable Care Act, aka Obamacare, was unconstitutional.

This is unlikely to affect health coverage for Americans for quite some time, but it does lead to further uncertainty about the ultimate fate of the landmark law.

Shares of rival insurer Cigna ( CI ) -- which is in the process of merging with pharmacy benefits manager Express Scripts ( ESRX ) -- and drugstore giant CVS ( CVS ), which recently acquired insurer Aetna -- were lower Monday as well.

Energy stocks were also under pressure after US oil prices shed another 2.6%, closing below $50 a barrel for the first time since October 2017.

And Dow component Goldman Sachs ( GS ) was weighing on the broader market too. The Wall Street investment banking giant is in the middle of a scandal in Malaysia.

The Malaysian government filed criminal charges against Goldman Sachs Monday due to its involvement with investment fund 1MDB.

Malaysia has accused Goldman Sachs of misleading investors about bond sales for the fund that were underwritten by Goldman Sachs. The Fed is said to be looking into Goldman Sachs' ties to 1MDB as well.

Shares of Goldman Sachs fell 3% Monday, extending its losing streak to nine days. It is now down nearly 34% this year, making the stock the Dow's worst performer of 2018.