I have just seen this thread. I have RA and Sjogrens and recently been diagnosed with low levels of VitaminD. Adcal and Theocal made no impression on it. The pain in my bones and joints was excruciating. As for the chronic fatigue, it's indescribable.
I am now on 25000 units of vitamin D weekly. My GP said he has never seen a patient on such a high dose. I need an infusion for my osteoporosis, but can't have it due to the lack of vitamin D.
All the autoimmune diseases seem to overlap. It's like "Buy one, get one free".
However, on a positive note, I think I am feeling a little better. ☺️.
I agree, when you have multiple conditions, it's difficult to diagnose which one is causing the problem. When my rheumatologist talked about comorbidity, I thought she meant I was dying?(as in morbid), Fortunately for me, that's not what it means! ?