I actually think you've already been doing a great job under very difficult circs, I agree with the comments that we're hoping for the best for both of you, and that you should not blame yourself about any of it. You are doing the best you can, the best you can afford, the best you know how, and trying to be publicly honest about your fears, which is courage of a whole different order.
I don't know if any of us can fully understand the burden of doing this after other experiences that are so close to it, but when we've cared for a pet like this, we can sure appreciate the efforts involved, and the uncertainties.
Good luck on it.