Thanks for the replies and support. After one night sleeping back at home, my son is back staying with my mum with me staying at home and spending some time with him during the day and my husband and I spending some time with him after dinner and putting him to bed before we come home to sleep. So far he seems to be coping with it okay and it is giving me the break I need, especially from having to get up to him early in the morning as I have not been sleeping well.
I went back to my dr yesterday and he increased my meds again, hoping that would help with my sleep, as well as my anxiety and depression, but last night was the worst night's sleep I have had in recent weeks - I was awake at around 2am and didn't get much, if any sleep after that. I still went and spent time with my son today, but lacked energy and it was left to my mum to do most of the hands-on caring for him.
In the coming week I should be starting an in-home parenting support program for parents with mental health issues that affect their attachment with their child (similar to what I would get in the mother/child unit), so I am hoping that will give me some of the extra help I need right now to keep trying to be there for my son and maintain that attachment, even if it's only in a limited way for now. I felt frustrated by my last session with my new psychologist, wasting time trying to get the wording of my "problem" right and not making any progress with giving me the help I am going there for (trying to manage my anxiety better), but I am going to try again tomorrow and see if it is any better.
My husband has said he is willing for us to stick with this arrangement of my son staying with my mum and us visiting him for as long as it takes me to get into the unit, even if it is a few weeks. I know I am not physically or emotionally capable of taking care of him at home myself right now and worry that I never will, that the support from my mum will become a dependency that I am unable to break. I worry about how that might affect my son and my relationship with him, as well as us as a family. I also worry about the strain that would put on my mum, who has health issues of her own and is getting older (she is 67yo) and her ability to continue that level of care-taking.
I have a lot of fear about the future and how I will cope and how my son will cope and how everything will turn out. I am so scared that everything will fall apart and I won't be able to put it back together again and my son will suffer because of it. I don't want that to happen, but I am really struggling to hold it together right now.