I trade mostly currencies but my impression is, watching price action for the last 2 or 3 weeks, that the market is rather spastic, with wild volumes one day, low volumes the other, making it hard for consistent day-trading... Is January the same as August in the sense that people might be on a vacation after finishing up the year ...? Seems odd...
The NYSE fully switched to the hybrid program on the new year. What you're seeing is the behavior of the new hybrid market. It's the total opposite of what the NYSE used to be.