First off, she has to get custody of you before she can claim any 'aid'. That includes state aid, which as a parent yourself you will be entitled to FOR YOURSELF AND YOUR CHILD. Your bf's mom can ask you to pay rent, which is sounds like she isn't right now.
Do you get medicaid already? If not, go apply for it. And while you are there, talk with your caseworker about what else you qualify for.
What are your daily needs? The fact that you don't have to pay for your food/housing/electricity/etc is a pretty good deal really. You have gotten excellent advice so far. It isn't going to get any easier - especially with a baby. In fact, its going to get a heck of a lot harder. Life is hard.