Hugs to you! I am so sorry you are going through this terrible situation. Please know that it is perfectly normal for you to feel upset and maybe overwhelmed and rather powerless right now, given the circumstances. I think it's important to validate that for yourself, and also to remind yourself you are doing absolutely the best you can at this time, we all are. When we know different, we do different.
Something that may help is looking at how you think about yourself and your life. I believe that our core beliefs about ourselves and our life are the programs by which we run our lives. So when we have a childhood where events made us feel like we were nothing, unheard, not validated or respected, etc, we see ourselves that way and that belief guides us into our lives, where we usually see it being validated. I think that people who are lucky enough to have a extremely blessed and emotionally well family growing up tend to think they are great and loved and their lives usually bear this out as well. I think many of us are around the middlish of either extreme somewhere.
How thinking like this helps me is that usually when bad things happen to me, they verify negative beliefs I've already held about myself and my life,and so it hurts all the more, and I feel powerless and overwhelmed. Now when something happens I can see I am in charge and I can take control. I see that I have a negative belief working itself out, and so I know that by addressing it, and working on letting it go, I can change my present situation. I often see the situation totally differently, and often circumstances just change themselves, once I am coming from a different place. I have had some hard times, and this has really helped me in changing my life for much the better! I still have a lot to do in this area, but it feels good to know I am working things out a little at a time and moving in a real positive direction.
Anyway, I thought maybe looking at things this way might help you, too. If this makes sense, and seems like it might help, you could start by affirming that you are powerful, (or whatever issue seems to be at the core of things) even if you don't feel that is true at first. As you keep constantly affirming it, you can work through and release past events that contributed to you feeling powerless in the first place. It sounds like your mother and home situation were at the heart of it to begin with. After validating your feelings as they come up, it's helpful often to be able to see that those who hurt us/are hurting us were hurt themselves, and so were those who hurt them, etc, because staying angry keep us tied to the pain we are working on letting go.
You can eventually let negative and self-defeating beliefs go, and allow yourself to claim your power now, which gives you the chance to change present events for you and your son.
Please know you are believed in. I am sending lots of love and good thoughts your way!