Although the action of market today is rather disconcerting, it is not totally unexpected. With nice recovery last couple of weeks, market is facing its resistance, for DOW/SPX, the resistance is its 50MA, for NSADAQ, its upper bound. If we believe that FED is going to base its decision on economy data, we are in for the day like today for the next few days, because, we will be inundated with the economic reports. There are data bound to be disappoointing, others may offer glimbs of hope. So, we will see pull/push for the rest of the week and maybe all to way to the FED meeting in the middle of September.
It is not good for the investors of course, but there are traders thrive on the volatility. so, it all depends on what kind of traders you are.
You can, of course, always chose no action which maybe very prudent for the corrent enviroment, and wait the market to settle down and until the market to show some clear directions
Or, you can chose short term trading. be open minded to trade both ways and take profit as quickly as you can, and always watch your back
so, Good luck to all of us