Oil prices continued to fall again on Monday as concerns of weak demand continued to worry investors.

Since the end of last year, U.S. oil futures are down 30 percent.

Light, sweet crude oil futures for February delivery fell to $36.81 on Monday, a 3.4 percent drop, Marketwatch reports.

Oil's past four trading sessions were trading up, but on Monday more worries and uncertainties surfaced, sending the prices back down.

There is a big concern that oil will be underutilized throughout the world, especially by Japan. Japanese data showed that the country had the lowest amount of oil sales in 46 years. Japan is the world's fourth largest crude oil buyer.

The Organization of Petroleum Exporting Countries (OPEC) says there is an excess of more than 2 million barrels of oil per day. That is more than 2 percent of world demand for oil, Yahoo Finance reports.

With oil taking a big hit Monday, energy stocks felt the effects. After a rally last week, energy stocks followed oil's decline by shedding their prices.

Marathon Oil took a big hit, falling to $12.98 per share, down almost seven percent.

Chesapeake Energy also took a big dip, dropping down to $4.08, down 8.4 percent.

As a whole, energy stocks dropped two percent, the market's sector with the biggest decline Monday. In the S&P 500, seven out of 10 sectors were down. Monday's declines in the S&P 500 put the index back in the red for 2015.

The stock market is in a holiday-shortened week with the markets being closed on Friday for New Year's Day. Monday, the markets were closed in the United Kingdom, Australia and Canada in observance of Boxing Day.

"It continues to show all eyes continue to be on oil right now and the real story is, when does oil come to a bottom, and what are the additional pressures from oil and energy companies that people are worried about," Jeff Carbone, co-founder and managing partner of Cornerstone Financial Partners told CNBC.

One of the few positives on Monday was Disney, which rose 1.31 percent to $107.25 per share after the company's new Star Wars movie earned over $1 billion in ticket sales worldwide in just 12 days.