Retest on Declining Volume
Retesting previous lows is a perfectly normal occurance in a bear market.  As of yesterday's close, we now have major index charts in which a major low was put in on October 10, and we have tested it twice.   

The psychology of this retest is as follows:
1.  On 10/10, panic selling drove the markets to an intraday low of 839.80 on the S&P 500 (7884.82 on the Dow).  5-day average volume on the SPY was 657,000,000 on 10/10
2.  The market bounced to 1044 (Dow 9794).  This was a quick 24% snap back in 2 days. 
3.  By 10/27, the market had sold off ALMOST to the 10/10 low, to S&P 847 (Dow) 8144.  SPY volume was 491,000,000
4.  Over the next 6 trading sessions, the market rallied all the way up to 1007.5 (Dow 9654).  Unfortunately, volume dropped off significantly on this 2nd run up.
5.  Yesterday, on 11/12, the market again fell to the support area, closing at 852.3 (Dow 8282.7).  
Taking a look at the charts, we see that volume has consistently declined at each of these three support tests.  This tells me that as the market falls, fewer and fewer sellers are entering the market, but still driving the indices down to the support level.  In a normal market, buyers would be stepping in to balance the sellers, in a flat market, or overtake them in a bull market.  Volume would remain steady or increase, typically.
The current action makes me think that as sellers unwind positions, there are virtually no buyers stepping in to take up the slack.  This is consistent with fund flows showing net money leaving the market over the past month.
Watch Your Bottoms
Going forward, these levels have become so obvious  that most professionals are now watching them.  If you follow this market, keep an eye on 839.8 on the S&P 500 (Dow 7885).  A close below those levels is bearish.  A dip below intraday, but then a close above is actually constructive, to some degree.  
Buyers will step in at these levels to try to "buy the bottom".  However, if more selling overwhelms the buyers, these support levels will be broken.  In that case, the next support level would be the 2002/2003 lows: