I am so sorry you are experiencing problems. I personally have been on steroids for over 30 years, taking it each day. Firstly in massive doses and then getting myself onto maintenance doses so now I manage my own meds. For me as a younger person it was a life saver at a time when it was regarded as the only medication to take for the severity of my condition. I had SLE and also JRA and was extremely ill.
I am talking here as a person with SLE and not from a medical point of view and this is just my opinion. Steroids are invaluable for some people, but others don't get on with them at all. Having said that it is most unusual for it to have the effect it has had on you in such a short time. Weight loss will go when your body gets used to the medication but the other things you menition seem so very severe. I wonder if you are on other medications that might be having an adverse effect ? Lots of meds interact and can cause no end of serious side effects. Even OTC ones can cause a lot of problems. Always check on these before you buy them.
Just a bit of info for you if you haven't got it already :-
Corticosteroids - prednisone/prednisolone (UK) - are produced in the adrenal gland naturally. The function of this gland is to produce horomones that then regulate salt and water metabolism - a bit technical but bear with me - and is the source of adrenaline which is the thing that gives us the 'fight or flight' action we need in time of danger, stress or anything like that.
This function is inhibited by large doses of steroids and turns off when they are taken. The gland does recover but it does need time and if you stop taking steroids abruptly, this will then lresult in no cortisone in the body. Most patients get very ill if they mistakenly stop their steroid therapy abruptly. When the dosage is reduced gradually, as it should be, then the adrenal gland gradually returns to full function. Once full function returns, the steroids can be completely discontinued.
Some people who have not been on prednisone for very long (usually less than one month) or who have tapered off with sufficient care that their adrenal gland is back to normal, can come off the drug completely.
I have highlighted the previous two paragraphs to draw attention to the fact that you can manage to get off it without too many problems especially as you have only been on it for a short time. I am by no means though advocating that you do come off it without first consulting your doctor. Also remember that you do not have to take any meds that you feel uncomfortable with. It is your body and you should have control of what happens to it. All medications and treatments need to be discussed thoroughly. There are other things that can be taken so again discuss the options with her.
I do hope this information is of use to you. I hope you begin to feel better soon. Take care.