Dear Man trying to be superman~
Welcome here, I'm glad you came. I think you already have a suspicion of what's wrong, it is in your title.
You have been brought up all your life in once culture, where your relations wiht other people from parents to shopkeeper is all very familiar, in fact you do not even have to think about it.
Now you are thrown into an alien world where I would guess every interactionis non-instinctual. You have to puzzle everything out. In a huge place like Sydney I would have overload and feel exhausted and lost.
Woud you like to say waht is scpeificaally troublng you at hte momnet? I can only talk in generalities otherwoise.
It does not mean you made the wrong decision in coming here, I'm sure your old environment had many faults, and like so many you have found you have grown.
I'm glad you have point of contact in your parents, it will be a help and comfort.
Perhaps in your new environment you are expecting to do too much too quickly.