It sounds like 5 mg is your "lowest effective dose." To be at 5 mg already after starting at 15 mg in January 2025 is doing extremely well. It isn't always about tapering your dose lower. My rheumatologist told me to find a "stable dose that worked" when I was newly diagnosed with PMR. I don't think a stable dose of 5 mg for a few months will do much harm. I assume you have enough prednisone to stay on 5 mg for awhile. If not, your primary care doctor should be able to tell you what to do until you see a rheumatologist.