I had to rely on my mayo Docs to get me out of it. C-diff has to be taken seriously, especially if you have U.C., which in your case is untreated. Are you at least taking any kind of oral or rectal mesalamine? I was surprised they put me on pred but they knew what they were doing in my case, and I started to feel better right away, and then quickly tapered off the pred within a few weeks. Hopefully you have a competent medical team you can rely on for advice.
OP: Hope it gets better soon.