Hi.
I can tell you as a person who had the disease and knows steroid calculator and the long term effects, and been a member of cushing's boards for years... here is some info...
5mg of prednisone is the dose that is sufficient to shut down your adrenal glands.
You are displaying the physical symptoms of Cushing's syndrome - the only way to get rid of them is to get off the steroids. The whammy is that some people will suffer permanent damage from the steroids, and some can come off with no damage. There is no way to tell. For instance, my tests showed mild effects, yet I had horrible physical damage and I am on permanent disability. Other people I know had sky high readings and came down, lost weight and had very little permanent effects other than the ghosts of the stretch marks.
Here is a steroid calculator - you will see (scroll down) that pred lasts 18-36 hours so if you take pred daily, you add pred on top of pred unless you use it up - obviously if you have cush symptoms, you are not using it up and the body has an excess.
http://www.globalrph.com/corticocalc.htm
I have NO adrenals and take 22.5 total HC a day to replace me - that is less than 5mg of pred. I would take less but my ACTH is excessively high and they want to suppress it a bit.
You must wean down carefully or you can die. Adrenal crisis is nothing to mess with. Right now your 5mg cuts are not so bad as you are way over your dose but when you get down, you will need to make finer cuts and wait between cuts. Listen to your body.
It is necessary to see if your adrenals will wake up - while you have only been on the meds for a short time - it was a large dose and you have to tread carefully to see if they are wakeable or not. I have seen others who have taken pred for asthma and then ended up dependent and addisian with cushing's permanently due to high doses of prednisone - overweight and steroid dependent. Prednisone is evil in my opinion. I will not take it or any of the long acting steroids unless it is an emergency.
Let me know if you have any other questions.