How much is too much?

[giddyup]

so, i used to play 5/10 6 max, beating it at a decent click. then i had to drop down to 3/6 6 max because of bankroll issues. I was then beating that at a nice 3.5BB/100 over the first 20k hands. now, all of the sudden i have hit a break-even stretch over the last 15k hands. i'm just wondering how normal this is, or what the hell is going on. also, has anyone noticed a change in the quality of play. is there any signs that people are getting better/worse, or that online poker is going to get tougher in the near future?