Low blood sugar can also cause fatigue because your body is working harder to stabilize your glucose levels. Fatigue caused by low blood sugar is commonly experienced by those diagnosed with diabetes. Along with fatigue, individuals with diabetes may also suffer additional symptoms including; frequent urination, excessive thirst, extreme hunger, unexplained weight loss, and blurred vision. Though all of these symptoms account for fatigue directly, many of them may contribute to an overall feeling of sleepiness.