Ricardo, I also have a daughter with complex issues and can empathise with how much one's one anxiety can be affected/heightened when a loved one is truly suffering.

I hope that when she sees her specialist and has had her diagnosis confirmed or otherwise then maybe a positive therapy plan will be put in place for her and she will have an expert to consult with as opposed to relying on primary care and the arrogant GP? I think Sjogren's is quite difficult to diagnose but if this does turn out to be the diagnosis then she'll be in expert hands and a lot of the uncertainty and anxiety could be dealt with at the specialist clinic?

You just need some answers and having a definitive diagnosis may take the pressure off you as to how to support her with a multitude of distressing symptoms.

As swajj says, you could also try a different therapist if this were an option? Sometimes it's hard to take that risk of another failed attempt but you could strike lucky next time?