Definitely seek professional help. I've been to a few psychiatrist in Sydney, though i'm not fully back to my youthful bubbly self, but i've seen significant improvements in my well being from my dreadful state 3 years ago.

Perhaps my experience with seeking professional help can give you encouragement. Therapy works wonders if you give it a fair dinkum go. Anti-depressants on the other hand are also helpful, but for the first few weeks are hell, it amplifies the shitty feelings before the therapeutic effects kicks in.

Too many people here are jumping to recommend that the OP seeks professional help without fully knowing the circumstances ...

Get in touch with family and friends, depression isn't going to go away if you push everyone away from your life. It's in these kind of moments when you need them the most, seek help from them.

Well the OP came looking for help.  Why wouldn't we recommend that he see someone whose career is dealing with these kinds of issues?

Anyway, I've suffered from depression most of my life.  I recently started taking anti-depressants and they've been helping me a lot.  So that might be something to consider.

Ow... btw.. do you drink Alcohol?

I would talk with a therapist and a doctor. Both of them together can come up with a solution to work through your depression and come to terms with what is at the center of the issue. It won't be a instant cure, and will take time, but depression is something that can be worked thorough. All we can offer is bits of advice compared to what a qualified professional can do.

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.

Some already said this here but I'm gonna say it again: SEEK PROFESSIONAL HELP!

One thing that I usually hear about people that felt empty and got over it is that helping other people, assisting them in their own problems helps a lot. You start to realize that you're not the only one with problems and some people have bigger problems. It's really important to feel useful in some way, to know that you're making a difference. There are some scientific researches showing that helping others is really good for our own health.

You should get in touch with people you like and trust; and talk with them about your problems: family and friends. It helps too. This way you don't need to carry all the burden alone.

Last advice: Pray for God's help. He loves you and He is always there to aid you. No matter what you've done and what others may say, He really loves you in a way you can't even imagine.

God bless you bro. You're not alone!
I wish you all the best.

Yes, it's true that the OP came to seek us out but there's no guarantee that he will be able to successfully receive the emotional and psychological support that he wants ... 

Therapy and drugs aren't always the solution. He could just be in a "slump" and that he needs time to self reflect ...

Dude, you gotta talk to someone qualified about this, especially if suicide has been in your mind in the recent past. Trust me (or anyone who's suffered depression), it does NOT just go away by hiding from it or ignoring it.

Things can only get better from here, but there will be some work involved. Seek out a counselor, even a free one through a free health clinic or whatever. Lots of therapists do a sliding scale when it comes to payments. They'll help you focus on what the problem is, how to react to it, discuss life goals and how to get there. It's never too late or a lost cause.

A great question that others have asked - Is your depression circumstantial? Or sort of an existential crisis? It sounds like the latter, in which case something like Wellbutrin or some kind of antidepressant may help to lift the mental fog and help you cope and make steps towards getting back on track.

You'll only get so far seeking help on these forums. You deserve happiness and a good life. Now go get it! Make the first step and call up someone who can actually help you. You're still very young and I don't want to see you waste years and years of your life being depressed, stuck, and in a downward spiral. It sounds ridiculous, but you have to love yourself enough to realize you're worth the effort. I firmly believe that.

Good luck, man. I really do wish you the best.

Edit: Really impressed by all the mature, thoughtful responses here. OP, you have some great advice to start you off. Now go make it happen and let us know if you need anything else.