Garthy, this website has the ability for you to start up like-minded groups. It offers the chance to do so @
http://www.samesame.com.au/group/create. Perhaps start from there.
Back to the initial post. I am a Sydneysider & know of other Sydneysiders of course and yeah, it's not dead easy to make close friends for someone that has lived most of their life here either. I don't think it has much to do with you being from Tamworth at all. It's just how it is. Making friends usually just happens in natural circumstances.
Perhaps pull back on the partying and go out as more of a treat occasionally. Also lessen the expectations, then if someone or something positive in your life comes along, it will feel more like a welcomed bonus. In other words, take the great importance off it otherwise it will only keep leading to disappointments. Sounds like you may have come to the big-smoke with "stars in your eyes" and when reality hit, you find it's not fulfilling its pomise (Pardon if I sound like a Dear Abbey column, but you asked for opinions).
Sydney has so much more than Oxford St to offer. It's just one small part.