I was diagnosed with GCA in late August and put on 50 mg of Prednisone. I am now down to 20 mg and have a dr.'s appointment on 1/2/20. Some of the side effects I have had include: trouble sleeping, fatigue, swelling of feet, bruising, and a puffy face. I suggest the book Polymyalgia Rheumatica and Giant Cell Arteritis: a survival guide. 2nd edition by Kate Gilbert. I have found it very informative even though it's mostly about PMR. Good luck and keep in touch.