A hundred thousand men were informed that they were invading the French coast and told to get some sleep before they boarded the assault craft and headed toward Normandy and a rendezvous with destiny. For some, the news came earlier but the following words were probably much the same, try to get some sleep. If there is one thing I can guarantee, the men storming those beaches in Normandy and parachuting into St. Mere Eglise et al were tired.
You have to spend days and weeks staring eternity in the face before you learn to sleep at such news. After you've done it for a month or two you just roll over and try to get a little more comfortable before falling asleep.