It was a major sell-off day on Wall Street with the Dow falling early 4% and the Nasdaq plunging more than 5%. Virtus\u2019 Joe Terranova gives his reaction and trading advice. Plus, Scott Wapner caught up with Doubleline\u2019s Jeffrey Gundlach about his investment strategy. Plus, the one part of the market Gundlach sees as being a \u201cgimmick.\u201d