You need to be able to accept the things you have done and learn to live with them before your mind set can change for the better. You can't dwell on it because it will cause irrational thinking and you will just repeat the same mistakes and it will make you feel more depressed that you pushed more people away.
Now that you are in Australia, seriously go buy a tent go camp near airs rock by yourself for a week and just recharge and reflect about the stupid things you have done without anyone's influence. Think of it like a spiritual cleansing quest.
Quacks will just put you on anti depressants generally. That is a short term fix that helps trick your brain by releasing a chemical. I now a friend who got put on anti depressants and in the end when he finally went of them he was worst than before he was on them.
