If you're experiencing these symptoms, check with your doctor, who will perform a simple blood test to be sure. Treatment usually includes medication.
Diabetics don't process glucose properly, which is a major problem since glucose is the body's main source of fuel. "As a result, circulating blood sugar levels are high, resulting in excessive urination, dehydration, blurry vision, and thirst. This leads to fatigue and exhaustion," Dr. Haythe says. Diabetes affects more than 29 million Americans -- 8 million of whom go undiagnosed.
Type 2 diabetes is usually caused by a mix of genetics and lifestyle, and although the stereotype of a diabetic is an obese person guzzling soda all day, skinny people can get it, too. If you experience any of the symptoms listed above, have your doctor run blood tests to confirm.
Millions of Americans have depression, and one of its many effects can be feeling tired all the time. "Depression is a common cause of fatigue and low energy," Dr. Haythe says. "Depression can take on many forms. For some, excessive sleep, fatigue, and an inability to get out of bed is common."