Don't despair...I have several ideas for you:  First of all...are you getting unemployment???  If not, file right away!  You should get income from that in about 4 weeks...at least that is what it is taking my Texas, where I live.  Even if you were working a menial job, self-employed, etc, you should still apply...let THEM tell you that you do not qualify.

Secondly, if your son's father is on disability, then he (your son) should qualify to get a monthly check based on his father's income.  May not be much, but it would be something!

Thirdly, you didn't mention about your daughter...are you getting child support from HER father?  If not, contact the Attorney General's office in your area and pursue it.  I know many women try to make it on their own, or don't want help as long as the man leaves them alone, etc, etc...but it is about the child.  They have needs, and the other parent should be paying part of those expenses too.

Lastly, you did not say if you were receiving food stamps, but if not, go apply!  You likely qualify for TANF as well, since you're not getting child support.  This office should be able to put the kiddos on children's insurance as well.  While you are there, ask about any of the other needs you and your children have.  I am sure they can direct you to where to go.

Blessings to you and yours!