@kimh. My onset to GCA was gradual, and unfortunately not recognized as such by E.R. doctors until I presented with loss of vision in my right eye. I was feeling very unwell, had "head pain" mostly on right side, fatigue, and had gone to E.R. five weeks in a row without that diagnosis.
I'm relieved you're in the care of a rheumatologist. Headaches are one of the symptoms of GCA. Mine presented as right-sided temporal pain at first, not headaches. My scalp was also very sensitive to touch, and somewhat painful too.

I'd suggest you research Giant Cell Arteritis on the Mayo Clinic site, if you haven't already. Knowledge is power!

Wishing you improved health soon.
Laurie