S.M.
Firstly, congratulations on your sobriety and being such a courageous woman and good mother. DO NOT STAY. It would be for all the wrong reasons, just follow your insticts and know it will all work out in the end.
Go to WIC (Women and Infant Children's center). If you are in the valley there is one on Sherman Way and Reseda (northest corner strip mall across from walgreens next to CVS) also one in the back corner on Sherman Way and DeSoto shopping center (near library). They will provide any nutritional needs for your child including formula. Just ask and they will tell you how to apply for and where to go to for financial aid, food stamps, housing, and medical insurance (medi-cal or Healthy Families) for your baby and possibly yourself.
There is a place in Northridge or Winnetka where you go to recieve all this but I can't recall the location. DO NOT WAIT! Go to WIC. Leaving your boyfriend will be the best move. Hopefully, one day he will get clean but until then you cannot risk the well-being of yourself or your child. If you leave while the baby is young it will be less disruptive for him. I hope you have family and friends who support you but even if not there are surrogates to be found all over this world.
I only wish my best friend were as courageous as you to take her three kids and leave her unhealthy relationship.
I don't know you but I love you for all that you represent. Good luck and good health to all three of you.