Hi @lilyonm, I was on prednisone a few days before I had the TAB. Do you get a regular CRP or ESR, blood tests, to determine your inflammation markers?
If you have any visual disturbance go to an Emergency Room immediately as undiagnosed GCA can cause blindness.
Did you speak to your doctor about your fatigue? Maybe your dosage of prednisone is too low. Have you seen a rheumatologist? S/he would probably be aware of other diagnostic tools for GCA.