Are you constantly feeling tired at work even after a good night's sleep? In fung shui, fatigue is caused by excessive Yin energy. Check out the lighting in your office, as it affects chi, or energy levels.
Is the lighting adequate? Is fluorescent or incandescent lighting being used? Or is it too dark? The frequencies of light emitted by fluorescent sources may cause fatigue to those who are sensitive to it. If you have any problems with such lighting, discuss it with your boss and modify the lighting, or move to a location where there is more natural sunlight. Ensure that the light of the rising sun - rather than the setting sun - shines on you. The energy at sunset has more Yin and may cause you to feel tired.
Make sure your back is not facing a window which faces west. Use curtains or blinds to block the sun's rays.
If you are sitting with a window behind you, check to see if any windows of neighbouring buildings are directed at your computer.
If there is, try to reduce the glare from these windows by using curtains and blinds, or reorienting your desk, as the sha chi from these windows can drain your energy levels.
You should also beware if there are shelves or structures above your head where you work. If there are open shelves filled with books, photo frames, travel souvenirs or work certificates, clear them and place them somewhere else. Having objects directly above your head affects your concentration.