I also think it would be a great idea to go and talk to your MCHN, GP or someone about it. Even the MCHN phoneline 13 22 29, 24hr help for mum's and dad's in Vic.
It can be so overwhelming in the beginning, especially if you have no help or support. It's hard. The sleep deprivation, the not knowing, it's a massive change anytime a new baby enters our lives. Please go and get some help.