This was a very important day from a technical perspective. And the reasons are very negative.
Notice the following:
Prices fell through three important areas of technical support today.
-- The first was the 50 day SMA
-- The second was the upward sloping trend line that started in mid-July (I should add this is a weak upward sloping trend line. I think the real line was the first one that prices violated in mid-August. But an argument could be made the second line was also a trend line).
-- The third was the lower line of the triangle consolidation pattern. The market has been trading between (roughly) 127 and 130 for the last month or so.
-- Notice the higher volume on today's action
-- Note the extremely strong downward sloping bar.
Today did a lot of technical damage. Let's take a look at the longer picture
The market is clearly in a down/up/down pattern. The market is also making a series of lower lows and lower highs. Also remember from above that today the market's broke a lot of technical support.
Short version: the possibility of going lower is very high.