chronic fatigue is often associated with weakened and overworked adrenal glands. the adrenals also regulate the body's potassium/sodium levels. they also play a key funtion in converting glycogen to glucose, which is important for anyone with diabetes. i would recommend doing some edreanl support herbs. here is some info on licorice and how it can help. i know nothing about the product in this link, but i think the info below is great.
extended use of licorice is contraindicated for those with hi blood pressure tho.
siberian ginseng, borage oil, and astragalus root are all fantastic to take for adrenal repair and nourishment. also vitamin C and pantothenic acid (vit B-5) are also critical. here are two very informative articles on the adrenals.