I am so sorry you are in such a grave and serious situation. Keep posting and reading. There is a lot of support here.
Al-anon provides great face to face support.
I agree with Hopeworks. Talk to a lawyer. You can't make good decisions based on fear. It is important to get real, professional, opinions about your options.
In my state there is a law that allows judges to confine pregnant women in detox centers. Another allows them to require up to nine months of involuntary treatment. A third makes drinking while pregnant a form of child abuse. I don't think that is common but there might be ways to safeguard your children that you do not know about.
I would arrange for daycare for your toddler while you are at work. Your toddler is also at high risk of being hurt either through neglect or alcohol related accidents in the home or in the car. I finally had to do this and the relief was enormous. My children were not hurt, thank heavens, but I regret waiting so long to do that.