I have been told by many credible doctors that, yes, fibromyalgia is indeed an autoimmune disease. There are many doctors out there who still do not believe it exists, that it is autoimmune, or that it lasts and doesn't go away like the common cold. Yes, I have doctor's tell me and even give me printouts stating that fibro is a short term thing from 1-3 months. I have had fibro most of my adult life and, no, it is not in my head as most doctors want me to believe.
My daughter also has it. I am also arthritic in all my joints.
That does not discount my fibromyalgia diagnosis in any way. I have been to may doctors. I know it is frustrating but with fibromyalgia, until the medical community make a definite decision on the cause and affect as well as treatments, all I can advise is keep searching for the doctor and specialists that will actually listen to you and work with you. They are out there. They are just hard to find. Best of luck and God bless!