The QQQQs closed in a precarious position today. They are just above support right below $43. The sell-off was on less volume than a big sell-off would probably entail, but is was also a weak day in the markets overall.
The DIA's sold-off on increasing volume. That's not good.
The SPYs sold-off on increasing volume. More importantly, the SPYs have decreased the last three days on increasing volume. Not good.