ES gap is 1338.00 to close of mar 31 at 1321.75. you're charting service might show close of 1324.00 for mar31, that is special end of month adjustment.
support inside the gap starts at 1330-1328, but a print below the 1330.25 level (although it might produce a short-term bounce) a print below 1330.25 would increase odds for a complete fill, at least to the high of the last 5 minute bar on mar31 (1322.75)
to me, this market has earmarks of panic sell on Monday. but I let the market show me and try not to pay too much attention to what I think. in the immortal words of Joe Ross, "trade what you see not what you think."