If you cannot keep your home, you cannot keep you home .. and need to take pride that you face reality and work with it.
Before you decide whether or not to sell your home, check out what you would be paying for rent. Where I live, $900 gets a one-bedroom apartment in an area of town that is not good but not dangerous to live in.
Your situation is difficult but perhaps not hopeless.
A roommate could help pay the mortgage. It would be difficult to bring a stranger into your family home, but not impossible. You would have to be VERY picky and selective.
A different job is absolutely necessary. Don't give up.
As for financial support, I assume you have a Court Order for child support payments? If not .. then you need to pursue this. If you do, does your government have an agency for pursuing fathers who don't pay child support?
Have you gone to Social Services and asked if there is any assistance, any daycare subsidy for low-income, or any educational assistance so that one can get better-paying work? I have no idea what, if any, services there are for single parents where you live.
Check out all alternatives before you make a decision about what to do for your house.
You see .. you pay $900 per month .. and 10 years from now when rents will be $1800, your mortgage will STILL be only $900. Well . .the actual numbers will be different, but the idea is that mortgages don't go up much over time, while rents DO go up.
And at some time, your mortgage is paid off and you pay nothing except repairs, taxes, utilities.