Connie makes a very good point: you should consider seeing an endocrinologist to make sure there isn't some imbalance causing your problem. An overactive thyroid gland can cause severe fatigue. Some of the other symptoms of an over-active thyroid include weight loss, diarrhea, insomnia, heart palpitations and heightened anxiousness. If this rings a bell personally, definitely see a doctor ASAP; it can easily be reversed with the proper treatment.
For general fatigue, you can try taking Rhodiola rosea, a natural herbal extract available in some health food stores. I had severe fatigue immediately after getting CK. After struggling with it for a couple weeks, I discovered Rhodiola (someone on this forum suggested it) and began taking it. With the very first dose, it cut my fatigue fully in half! YMMV, but a few people on this forum have reported similar results. Rhodiola has no caffeine content and has no side effects, with one caveat: don't take it past, say, 2 PM or it might keep you awake at night.
Best wishes,
TW