What would have happened had D-Day been lost?

Western Allies (Britain, US, etc) wouldn't have landed in Europe. By June 1944 (the D-Day Landings), the Soviet Union (Russia) was aleady approaching the German's front door. Translation: If the Western Allies didn't reach Berlin, the Soviets would take it over first. Germany would have lost the war, regardless of the Normandy Landings; the main war was between Russia and Germany, and Germany was losing.