I'm sorry you are in such a dark place, CL.
When I retired, I was gifted with "The Book of Joy" by the Dalai Lama and Desmond Tutu. I am an atheist, and I didn't think this book was going to be my cup of tea. I actually got a lot of value from it, especially when I was dealing with some health issues of my own and then my mother's Alzheimer's diagnosis. It was the chapter on acceptance that I found really helpful. "Acceptance - whether we believe in God or not - allows us to move into the fullness of joy. It allows us to engage with life on its own terms rather than rail against the fact that life is not the way we would wish." The book also said "Acceptance, it must be pointed out, is the opposite of resignation and defeat.... We are meant to live in joy...This does not mean that life will be easy or painless. It means that we can turn our faces to the wind and accept that this is the storm we must pass through. We cannot succeed by denying what exists. The acceptance of reality is the only place from which change can begin." I personally found this to be a useful and compelling message.