Moving up from $10NL to $25NL is a big jump, at least for some players that have been grinding away at the micros for so long. That's not say there aren't a ton of fish at that level, but you should be using a few more strategic moves than before. Are you not playing as much ABC poker? 6k hands is small so maybe you are just running bad.

Sorry, I'm not one for stats so I'm sure one of the regs will give a better answer.