Prednisone as a diagnostic tool

Has anyone else had their doctor use prednisone as a test when trying to evaluate for RA?

I am finally down to the 3rd day of 10 mg.....

The first 6 days on 30 mg were great. Morning stiffness almost gone, pain 80 percent improved, at least. And the fatigue was gone. I felt like a normal person.

The second day of the taper to 20 mg, things got ugly. Exhaustion. Dizzy. Spacey. Pain coming back. And a brand new heel/foot arch pain I never had before.

I am now on 3rd day of 10 mg and more of the same. Yesterday back soreness/stiffness started along with feet. My usual joint pain is creeping back in, too.

So. I know enough to know that this suggests something inflammatory. But I am confused b/c pred. can also be used to help OA, right?

How does a trial does help them point to RA if pred. can also treat OA?

Also.....how the heck long am I going to feel this terrible? I mean, pain coming back is one thing.....but I feel ill. How long does it take to get this out of your system?

Is there anything I can do to lesson the awful tapering side effects?