i'm so sorry hunny
first bit of advice is to find a counselor. ASAP. You sound like you are dealing with horrible depression, whether it be postpartum or from the bad situations you've had to deal with or a combination. I'm not sure of your financial situation but please do not put off finding help. Not only will it be good for you but will also help if they do try to get custody because of your depression. It will show to that are trying to improve the situation. I am so sorry you've been cutoff from your stepson. Please don't let them make you think its your fault. I know how it feels to love a stepchild and have them torn away. Also see about filing for custody now. You don't have to be divorced to do that and the quicker you do it the better. Continue allowing him to see his daughter but if his family can't be civil to you then don't bring her there. Meet in a different location to let him visit. I'd be wary about letting him take her by himself until you get a order filed for custody. You should be able to get the papers and do that yourself if you don't have a lawyer. If he wants to divorce you then let him. You deserve someone who loves and supports you. You are not an awful person. Things can get better. Please keep trying and don't give up hope for yourself. Feel free to PM me if you need to.