G'day from another Sydney sider. There's quite a few aussies here and Paleo_Rob has started an Aussie group, I am sure he'll chime in soon and direct you to it (I'm hopeless figuring these things out, I am sure if you can't find it look up my profile and it must be there somewhere).
The grogginess is all part of the carb flu, which I am sure yo have read about if you have dug around a bit. Press on, you'll feel amazing in a short while. I think its easier if you cut as much crap and carbs as possible as soon as possible, but others suggest a gentler approach. The community here is awesome, so if you are having doubts, hit the forum!