Sorry to hear that.
For income, if you are in the US, you have a few possibilities.
First, your ex better be paying child support. That money won't really help you, but it will ensure that your baby has food.
Second, are you getting unemployment? If not, why? If your firing was unjust, you may also have a case against them.
Third, there are public programs for unemployed mothers with young children. I would investigate them. In the US, there is also a program called SSI which may be useful if you can claim disability due to your eyes. It sucks, since it sounds like you can technically work, but not being able to drive will limit your search area. Almost any public assistance program in the US is going to put you deeply into poverty, but its better than starving.
Also, a few job hunting recommendations: Gas stations. Hotels (housekeeping (sucks) or front desk). Fast food (sucks). Government jobs (dmv, post office, etc -- dunno the requirements for this, but HTH). And you can probably make a few bucks selling plasma if that's available locally. If you are desperate for money, almost any job is a good job.
I don't know what to do about your mom, its a hard situation. You probably love her, but it sounds like she screwed you and her grandchild over pretty badly.
Perhaps its time to limit the amount of influence she has in your life. Its mean, and she probably will be offended, but your priority should be protecting your baby, not dealing with the fallout from your mother's scheming.
Hope it gets better.