There seem to be a lot of concerns right now - China, tariffs, oil, yield curve, misc. tail risks, etc. But the fact of the matter is that consumer confidence is still high and that's about 2/3rds of the economy.
After the sugar high of last year's tax cuts, it was inevitable that there would be a hang over. Add to that what I think is some fairly aggressive tightening by the fed, which isn't unjustified given the state of the economy and things were bound to get rocky.
What concerns me is the fact that tax cuts should have had a longer effect than they did. Over the past 6 years the money multiplier has gradually been inching up but we're still no where near pre-2008 levels.
https://fred.stlouisfed.org/series/MULT
Personally, I think that needs to recover quite a bit before we have any real danger of inflation, but obviously the fed doesn't see it that way. Balance sheet normalization is on autopilot plus you have the Treasury issuing roughly 300-400B in new debt due to the tax cut. As long as that's the case the market is going to be governed primarily by liquidity issues.