Sick sisters...what could it be?

[LittleBunnyFooFoo]

Hi...I am a 31 year old woman. My sister and I have had slowly progressing fatigue and pain as well as cronic diarrhea and frequent infections for many years and were told we had Fibromyalgia but I did not think the diagnoses fit us very well. Our hair is thin on our heads but thick on our faces, our skin is changing and becoming more rough and hyperpigmentated areas and strange marks...then my sister began to have seizures, eventually a few years later I began having seizures as well.......at present we are cpmpleatly miserable and I fully believe this is something familial and more serious than fibro and Epilepsy. Our grandmother and mother show SOME of the same symptoms excluding seizures and the only common link we can find is that grandma had her thyroid removed, mother has enlarged thyroid and my sister has enlarged thyroid as well. I thought maybe hashimotos or something but they argue with everything I want and it is like pulling teeth to get them to do anything for me, I have gotten the doctor to draw blood to test my free thyroid hormones but she refused to do an antibody test too....I am waiting to see what that and an ultra sound reveal but what should I do if they tell me yet again they see nothing?? What could it be...I think it is likely autoimmune. I am nearing the end of my rope....I need some help figuring this out because the doctors won;t spend any time on me.