Headed into the Beartooths yesterday for a scouting trip. About two miles in I hit the wall and ran out of energy . Wife told me I was white as a sheet and my eyes were dark and sunken . Severe cramping in my legs and sick to my stomach. Elevation was only about 7,000 feet .I have hunted Colorado at 11,500 and did ok . Barely made it back to the trailhead . Elevation sickness ?