Another point to consider is that often atypical lupus, Sjorgrens and RA are linked by common chronic infections. For example, our research has found that chronic infections like Mycoplasma species, found in about 45% of RA, 50% of lupus and a majority of Sjogrens, can cause all of the signs/symptoms that you list and many more.
These chronic infections can be treated (go to Treatment Considerations, www.immed.org) successfully.
Prof. Garth Nicolson
You may have already done some research, but here are a few sites to help with this.
http://www.medicinenet.com/sjogrens_syndrome/page3.htm
http://www.labtestsonline.org/understanding/conditions/sjogren-2.html