<s>How about exercising? If you have spent the day doing smurf all, there is a tendency to being tired for no reason at all. Go swimming, ride a bike, walk a mile, or something and you can be surprised at how much more energized you can feel after doing something which should tire you out.</s>

After consulting Google, I can positively tell you without any doubt you have a brain tumor and are dying. You may have to drill this one out.