That seems like a very fast taper. It's been a few years since I've been on Pred. but with normal tapering, I was always on it for about 8 weeks. I was tapering down every week, not every few days. It could very well be from the Pred and the tapering.
Female, Age 38
Diagnosed w/c.diff 7/02 when pregnant w/1st and only child during 2nd trimester(wasn't on antibiotics)
C.diff flare within weeks of delivering baby 1/03, Diagnosed with UC 2/03
LDN - 2/17/09 1.5 mg., increased to 3 mg. 3/3/09
Acidophillus, Sacchromyces Boulardii, Oil of Oregano