Dude, don't ya just hate that? I get the same sometimes. We don't think rationally about fatherhood/husbandhood when we're under financial pressure. Relax, you are not mis-handling money. I mean, you're not gambling are you? You're not buying grog at the local instead of food for your family are you? Sydney's a VERY expensive city and the first couple of years of marriage, a new job, a new baby on top of that fact mean you really don't need to considered yourself a bad husband and father because of it. Ps 73 is always nice to read at times like this. It's not until about verse 16 or 17 - when he goes into the sanctuary of the LORD that things get much clearer and much more hopeful. I'll be praying for you.
As I read it, it seemed to me a good combination of practicality, sympathy and Christian encouragement; all areas in which I struggle. So I thought I'd preserve the advice here in case it is of help to anyone.