I'm not in any right position to say "she will be ok", but she will be ok even if it happens. I will pray for you instead.
My dad was diagnosed with "possible" pancreatic cancer with all kinds of symptoms at the age of 82, he doesn't even wanna find out if it truly was a cancer, until he was taken away by the sickness. We all felt sense of relief after the postmortem confirmed it was indeed the final stage cancer as we didn't put him in all kinds of suffering a normal cancer patients do. I am not sure why I share this with you, I guess I am trying to tell you I know how it felt with my dearest dad.
RE: Finding out your doggo buddy is dying... it's not a nice feeling