Definitely get rid of the carefresh. It is extremely dusty and that could have easily contributed to her respiratory problem. It causes respiratory distress in rats all of the time, which is the reason I will never use it. Plus, it stinks, and just looks gross.

I would just use newspaper for her for the time being, and keep her humidity in the 60s to 70s, but not wet. Make sure her temps are higher than normal too, as that will help the antibiotics work faster and will help her immune system. It sounds like the vet gave you Fortaz, which has to be kept in the freezer after it's mixed up. Good, but expensive, antibiotic.