My 15 year old boy who is very active and plays hockey about 5 x s a week is always very tired. Wants to sleep constantly but forces himself to get to hockey or training. Eats very well but has great difficulty concentrating. Drinks plenty of water. Has recently gone through a major growth spurt. He is 15, 5 10 and weighs 155 pounds. Has black circle under his eyes and when not doing something physical he sleeps, hard staying awake at school.