Or it may be the sign of a too hectic schedule. Some fatigue in life is to be expected. But if you experience a marked change in your energy level or your fatigue persists despite adequate rest, see your doctor. Being tired all the time may be a sign of an underlying medical problem. If you're burning the candle at both ends, you're going to feel it.
Anxiety can also cause fatigue.
If worries are keeping you from relaxing, you're likely not getting the rest you need. Don't try to do everything. Take time each day to simply relax. Try to build 20 to 30 minutes of moderate physical activity into your day. Then refuel every 3 or 4 hours.