Telechart has a good breadth indicator called T2108, it shows you % of stocks above 40 day moving average. As of now only 14% of stocks are trading above 40 day MA. That shows you the damage caused by selling in last few weeks.
However markets tend to be mean reverting. This tendency is more pronounced on short side. Market weakness tends to be short lived and attracts buyers.
If you study the S&P returns since 1926 that I posted some days ago you will see on calendar basis only 11 times in last 90 years the market have had 10% plus year to downside. Implication is probably we will recover from this downturn sometime during this year.
Periods like these are very volatile periods and if you do not have right strategy you can get chopped to death.