The main thing to keep in mind is that $SPX has not broken down below support at 2800. It was tested — more or less — once again yesterday and has held so far. A close below 2800 would be very negative from the viewpoint of the $SPX chart.
Overheard, the major resistance on the $SPX chart is the double top at the all-time highs. More than one bear market has started from a similar pattern.