Many people have autoimmune conditions. The trouble is, not all of them have proper diagnoses.
I have one that my physician and I can clearly identify: Hashimoto's hypothyroidism. And like many people, I follow the pattern that once you have one autoimmune condition, you're often prone to others.
Unfortunately, Western medicine hasn't been able to diagnose the second condition as concretely as the first.
So until that time, I continue to research and try to manage my health as best I can.
A yoga friend and colleague recommended this book, Solving the Autoimmune Puzzle. It's one of many I've read on the topic. I'm almost done with it, and my general assessment is that I've heard many of this doctor's observations and suggestions before, and believe I can continue with aspects of diet, exercise, and stress-relieving techniques, as well as the proper medication, to help manage my condition(s) as best I can. This book does contains a couple of points I've not considered, so I'll continue to research those.
If your physician indicated you have an autoimmune condition, you might want to take a peek at this book and see what aspects of it might apply to you.