Once in your bed, you can't relax. Take care of this kind of mental activity during the day. You check it regularly, between tosses and turns, throughout the night. You will definitely be tired and cranky all day. The clock has told you so.
Many sleep experts advise turning the clock to the wall.
Grant-Gray suggests you train yourself not to check the clock and learn to concentrate on falling back to sleep without worrying what time it is. While awake, she suggests, enjoy the quiet of the night. Don't worry that you'll never get to sleep, she says. Don't say it. Don't do it.