How do you know if your good enough to beat a limit?

[me454555]

I'm a winning player in general. Over 60k hands at various limits I've been a siginificant winning player. I'm well bankrolled and pretty well read. I know the basics and can beat the LLs so like most good LLers, I decided to move up to the 5/10 6max game.

Over the course of the game I've met some of the worst online players I've ever met and over my first 5k hands hand a great run where I won 250 BBs. Then over my next 5k hands I've almost all of it. I realize I'm not the 5bb/100 winner I was during my frist 5k hands and I'm not the 4bb/100 loser I was over my next 5k hands. I'm somewhere in the middle. So how do I know where I stand? How do I know where I play? I feel I stil make a lot of mistakes @ 5/10 6max but I feel I should at least be breaking even. But its been almost 2 weeks since my last winning session.

What should I do? Should I drudge on @ the limit I'm currently @ and hope the pendulum will swing in the other direction or should I drop down in limits to rebuild? My biggest fear about dropping back down is that I can beat the game w/out improving much. Will dropping down stunt my growth as a poker player? Is this just typical 6max varience? This is the first time I've felt overwhelmed by a new limit or game. I've had downswings like this before but I've always had a couple thousand hands to back me up that I'm a winning player. In this situation, I don't have that data to say I'm a winning player on a losing streak. I guess the real question is how do you know if your a winning player on a downswing vs a losing player who had a good run?

I feel very lost so any advice is appreciated.