Hi, Jody. There's actually a lovely medical term for that all over unwell uck feeling - malaise. So if you ever see in your medical records - patient complains of malaise, now you know that's what you had.
I always notice when I'm tapering down that I feel better for a few hours after the AM dose, and seem to gradually feel worse as the day wears on - I assume it's the effects of the steroids wearing off. The mouth ulcers are usually the tip off for me that a flare is starting, but every person will have a different pattern of symptoms.
During this last taper, my rheumie recommended DHEA to counter-act some of the steroid withdrawal. I take 50 mgs. daily and the muscle pain and fatigue don't seem as bad, so I'm actually managing to taper off on schedule for a change. So you might ask your doctor whether this would be okay for you.