All the above, EXCEPT ... self-publishing needn't cost you thousands. There's at least one company that will do it on a single-book basis and if you get the right company then you could have good deal. But you need to do your research and not get taken in by companies who tell you they'll make you into a bestselling author. Self-publish, and the person who does the promotional foot-slogging is you, no matter what fancy marketing package you buy. It can be rewarding and fun, but there's perhaps less than a one in a million chance you're going to make it big from this.
I think perhaps the best way of pushing yourself is to find some sort of unique selling point about YOU. You call yourself a 'nobody', but I bet you're not. Many people in seemingly mundane jobs and with seemingly mundane (but troubled) lives have written successful books about their lives, because there's something about those lives that have been interesting to others. You say you have given up on god. That's a bit of a hot topic these days and I for one would be interested in what you've got to say on the matter because I too have a far better life without it.
Maybe people are just fed-up with reading about the Jade Goodies and Gordon Ramseys of this world and, just for once, would like to read something about an ordinary bloke coping with a difficult life without having to resort to religion.
WAYB will has lots of listings of agents and publishers and what sort of work they're interested in. It also has a number of articles aimed at helping first-timers to succeed.
Good luck, and let me know when you're published.