How long can a good streak last?

Hi guys.

So how many hands do I have to play before I can be confident I can play this game?

Bit of background:
I know Im a winning player, but it was never to the rates I was satisfied with.
I found this place. Won nicely at 2/4 and moved up. I then had a dry spell at 3/6 and Harv72 gave me a post containing several great pieces of advice which i feel has transformed my game.

Since then I have gone at just over 3BB/100 over 21000 hands. 1.7BB over 11000 at 3/6 and 4.4BB over 10000 at 5/10.

So, when will i crash and burn?

I read of people beating these games for 3BB/100 but I find it hard to dare to believe it might be me. I know I cant hold a candle to some of the guys on here, but I just seem to be coming accross some many horrific players, my mind starts wandering. 4 guys cold called my EP raise 5 mins ago. They all folded to one small bet. Laughable!

I know bad times loom, but im curious as to how long people go on rushes. 21000 isnt a lot, but it isnt a tiny sample either.

Anyway - thanks for listening. I plan to post my PT stats soon as it proved very helpful last time.