Where do I go from here?

Well my heart is just breaking right now.I can't even talk to my kids on the phone because my ex is having a bad day.I want to fight for custody of my kids, but I'm afraid to go against him.I've had 2 jobs in my life I live on ssi,and I'm a recoverying addict.It just seems like he's the better provider.I love my kids and miss them so much.I am trying to get a job right now,I just don't know how I could ever win against him.It's not fair to my kids what he's doing.I'm afraid of losing.I've always lost and always failed.I want a life back to be the mother I once was, but even better.How do I get the right help to fight for my kids?I graduated rehab in Jan of this year, and I stay on my medication.I just need a job, and to be independent so I can oneday have my kids back at home with mommy.I wasn't going to put all of this out there, but I can't keep it in anylonger.If anyone has any advice please could you give it to me.Do I just keep pressing forward,and give it to the Lord?I'm new in my faith and it seems the devil is trying to break me.I REFUSE TO FALL.God is on my side,I know I can do this.I'm just struggling with the feelings in my heart.