Personally, if this were me, I would assume that it was me, and not varience.

Therefore, I'd be pouring over and analyzing my hand histories, replaying hands in Pokertracker's gametime window, and rereading sections (or all) of SSHE.

It might be due to varience, but it's not going to hurt to do the above, either.

As Webster also pointed out, try doing some other version of Poker, like Omaha (I have yet to try) or Stud. Or, just play on table of full ring or 6 max and really concentrate on your play and the other players. Think about what you are doing, try to avoid surfing the web, and don't put yourself on auto-pilot.

Good luck.