It may seem as if the market is slowing down, but if it is, it's only in a relative sense. $SPX made new all-time intraday and closing highs on each of the last two days, and $NDX (QQQ) did the same. The Dow ($DJX; DIA) and Russell 2000 (IWM) are only one day removed from all-time closing highs.
All one really needs to know is that the chart of $SPX (and the others) remains strongly positive. The first support level is at 3725-3750. Below there, the next support area is 3630-3650.
The market remains overbought in many areas, and confirmed sell signals are beginning to appear. However, the most important indicator (the chart of $SPX) remains in a positive uptrend. There is support near 3725, more important support at 3630-3650, and then 3550.
On Monday, January 4th, the new year got off to a rocky start as selling built and exploded into a 90+ point selloff in $SPX. However, the decline bottomed at 3662, and the market has been rallying ever since. That brief selloff seems to have rejuvenated the market, and not only are new all-time highs being made, but they have been accompanied once again by rapidly expanding breadth.
It looks like things are going to be very interesting in the new year. The market is strong, as evidenced by new all-time highs in all of the major indices this past week $SPX, $NDX, $DJX, and $RUT (although $RUT has faltered a bit in the last couple of days). Since price action is the most important indicator, the overall trend remains bullish as long as $SPX holds above support.