I agree with those who have posted so far. I ran into a similar problem with a GP who refused to continue prescribing prednisone while I was waiting months for the rheumatologist consultation. Stated I did not have PMR, although my symptoms were classic and I was dramatically improved within hours of a single 20 mg dose of prednisone. I immediately changed my circle of medical professionals, called the acute triage desk and set up an urgent video visit with a nurse practitioner. Fortunately the NP was very knowledgeable and prescribed enough prednisone to cover me until my visits with the new doctors. The new docs have been happy to prescribe pills in whatever sizes are most convenient, such as 1 mg, 5 mg, 10 mg, as needed. I have been tapering for a year without problems and remain in a high quality remission.
You, and in fact we all, deserve to be treated by competent medical professionals who understand such a simple yet monumentally important issue such as prednisone dosing in autoimmune disorders.