I'm sorry to hear how your daughter is feeling. My daughter with CF is 20 and I can't explain to anyone the feeling I get watching, listening to her and seeing the affect it has and she doesn't have as many problems and she copes really well compared with many others with CF. My heart just breaks for her and all kids and adults with CF. In the good times when they are "well" it is hard to imagine as CF can seem "not too bad". Then it hits and Wow, itis the worst disease ever and is heartbreaking.
I myself have taken Prednisolone for bronchiectasis & apba and it does awful things to oneself. I know at times it is imperative to take but whilst on it, it can cause one to be very depressed, confused, unable to eat, unable to stop eating, hair growing on face, bloating, crying, muddled, chest feeling like in a vice. All kinds of things particularly feeling like in someone elses body and just not thinking with clarity and the feeling of the "joy" just gone.
I think the drugs have a lot to do with emotions and I am thinking of you both and your loved ones. From my experience it is hard to feel, see anything clearly when on steroids.
Warm wishes
X