I felt just like this for almost a year. Eventually it ate at me so bad I was physically sick.
I talked to my doctor - the first person I unloaded on in a year.
I got help for my physical health, began IC and slowly but surely started learning how to take care of myself.
By the time I got healthy again things started to unknot. It never seemed to unknot totally until my son gave me a wonderful gift of noting my struggle which I thought I hid and telling me "no matter what happens with dad and you, I know you both love me and I'm lucky, I WILL be ok". Before that, I thought a D would kill him, his dad would do psycho stuff, and imagined all kinds of horrible messes.
I saw something somewhere that said no way past it but through it. I think my imaginings, thoughts, and "plans" made going THROUGH that much harder.
If I could go back and talk to myself a year ago I would tell that me to go slowly, impatience only increases the insanity, there is no hurry, let things unfold, feel and understand myself, be true and honest with myself and take good care of myself, no matter what I and my SON will be ok.
I'm so sorry you are feeling this way rbf. But please find some small hope to hold onto. It will be ok, it just might take time.
I hope you can find some support, here, IC, ...somewhere.