So, I've read your thread, but one thing still isn't very clear to me - what does your H give as the reason for his sudden change of heart?
You say it came about after your bachelor party/bachelorette weekend? Is it connected to that in some way? Did you do something he didn't approve of (stripper-gram?) OR do you suspect HIM of being unfaithful (sleeping with a stripper?). It just seems unusual that it happened so suddenly at that point.
Now, it might just be that the pending "official" wedding didn't seem real until the bachelor weekend, and that gave him second thoughts. Or maybe his groomsmen tried to talk him out of it for some reason?
I'm also curious - what was the reason for the "secret" first wedding anyway? My sister got married this way - eloped, then came home and planned a "real" wedding without telling anyone they were already married. Her H cheated on her before the second wedding. (Eventually they divorced, several years later, and he has proven to be a prime example of "the sociopath next door").
Something is very not-right about this situation, and if it's not obviously attributable to something you did that he took legitimate offense at, then I'd start looking for the Other Woman.
Meanwhile - you DO need to figure out how to support yourself and your son. Even if your H comes to his senses and comes back, you really don't want him back until he can prove he will be constant and not a disruptive force in your child's life.
Do you get child support from your child's father? If not, can you be doing anything to get that?
I like the idea of a school-district job - that saves you from a lot of childcare expenses, and usually includes benefits. You can always get a part-time job in the summer if needed. But if it's not enough to support you right now, what can you do to earn extra money on the side? Can you babysit after school or evenings? Do you have any craft skills you could sell online? Resell thrift store finds on eBay?
Keep looking for a place - you might need to share a house with someone at first. Eventually you may be able to find a landlord who is willing to overlook your income. Take a look at these two resources to give you inspiration for managing your budget: The Tightwad Gazette books, and the mrmoneymustache website. Both of these will give you ideas and motivation to figure out how to live within your means and get ahead.
As far as leaving the house - he may have to evict you if you stay - that takes some time, as I understand it, so I'd stay put as long as you can and save up your pennies.
Also - look into what you would qualify for once you are divorced, in terms of things like food stamps, head of household tax filing, earned income credits etc. You might be able to increase your exemptions next year and take home a larger paycheck, which would look better to landlords.
If you're not good with numbers, find a friend who IS and get them to help you to put together a budget and figure out how you can live on your income.