Excessive Coffee

It is said that too much is as bad as too little. Coffee is like. I averagely drink three cups of coffee everyday at work. The day I exceed the average I am barely able to go to bed. I can't not get a wink of sleep until dawn. As I know the side effect of drinking too much coffee a day,  I try to refrain from drinking larger than usual portions. It is, however, hard to overcome temptation. When I stay up late at night due to coffee I drink daytime, I do Google or Internet, lying down on the bed of the dark room. I keep feeling awful next morning. How stupid it is!