Do you have that run down, sluggish feeling? Feeling tired often signals emotional stress, physical illness or lack of healthy involvement. Here are a few of the most common causes of fatigue and some tips on how to combat them: 
Not Enough Sleep
Sleep disturbance is a common response to change or stress. If your nights are restless, avoid caffeine after 6 p.m. Go to bed at a reasonable hour; do moderate exercise; and skip alcohol in the evening and before bedtime.
Crash diets or overeating may be a cause of sleepiness. Losing pounds too fast can prevent your body and mind from functioning properly. For a diet that will keep you healthy and energized, eat a variety of foods low in fat and high in fiber. Do not eat big meals, and avoid heavy snacks at night.
Lack of Exercise
Regular exercise improves your appearance and physical condition, and it gives you more energy. Exercise enables your body to send oxygen and nourishment to your muscles and brain more efficiently, increasing your endurance and ability to be more thoughtful and alert. Regular exercise promotes overall feelings of well-being and enables you to better handle the emotional and physical difficulties of life.
Over-the-counter drugs, prescribed medication and street drugs (including alcohol), may cause fatigue. If you are taking a drug that you suspect, talk to your pharmacist or doctor. He or she will be able to tell you whether it's the drug or a combination of drugs that is causing your drowsiness. If you are consuming alcohol on a regular basis, try cutting back. You may discover a whole new level of energy and involvement.
Energy is needed to cope with the every day pressures of life. If you are experiencing high levels of stress, you may feel overwhelming fatigue at the end of the day. Consult with a counselor who can teach you stress reduction techniques. Use them to break those tense and anxious feelings.
Maybe you're just not involved enough in life. Try doing something different. Take a walk, go someplace, visit friends or start a project that interests you. People who are truly involved with life are rarely tired or bored. Instead, they look forward to the adventures of each new day.
If the above conditions don't explain your weariness, you may be suffering from something else. Anemia, diabetes, heart disease or depression may play a part in causing your fatigue. Fortunately, most fatigue is not serious but if you have chronic unexplained symptoms, consult your doctor.