Hi there, I did the exact same thing as you (at Google Sydney), before eventually deciding that I must strike out into the wilderness.
In the few years since I left; I worked as a solutions architect managing a team, a team lead, a remote dev, and now in a startup. Front-end, back-end, flip-side, all the ends. So I've been deliberately trying different angles of my career to see what suits.
I'd describe this process as grueling, ("challenging" is too friendly). I honestly think I would have been happier staying at Google, farting around, and being social. I agree with a lot of the comments here. However it's a catch-22, because the me that exists now wouldn't choose to go back and overall I think this has been good for me – and not just because of the, er, _character building_ aspect of it.
If you stay at Google, make the most of it by progressing deliberately in your social life. If I'd've stayed, I could have comfortably raised some kids with my wife by now - but that's still on the todo list.
If you leave, just jump right in. I didn't study anything, I just picked it up as I went along. If you were able to follow Steve Yegge's advice and Get That Job At Google, then I'm sure you're a smart cookie and can fake it til you make it.
Basically I'm saying you can be happy either way. If you leave, know what you're getting yourself into. If you stay, don't waste this time but use it on yourself.