Jed had ehrlichia. Stress would always cause a flair-up. When he would flair, his symptoms were peeing (A LOT), panting/pacing and high fever. He was mis-diagnosed with UTIs by our former vet. Our current vet almost immediately diagnosed a TBD. A blood panel confirmed it. We would dose with doxy for a minimum of 6-weeks. Sometimes he would get a prednizone shot at the start of the treatment.
I hope you can get Rudy's illness pinned down so that he (and you) can start feeling better.