@nancygreen Welcome to Mayo clinic Connect. Having a rare kidney disease can be very frustrating, most definitely! I myself was diagnosed with Type III Collagenofibrotic Glomerulopathy in 2015. There have been less than 50 people in the world ever diagnosed with it!

Fibrillary glomerulonephritis is also considered a rare disease, with no known cause, but certain autoimmune conditions may lend a favoring to it. Here is a pretty good article from the University of North Carolina Kidney Center, that you might fond useful:
https://unckidneycenter.org/kidneyhealthlibrary/glomerular-disease/fibrillary-glomerulonephritis-gn/
Are you able to see a medical team at a major teaching hospital, or even Mayo Clinic?
Ginger