Unusually tired lately, dont know whats wrong.?

HI. Lately i have been noticing very strong fatigue. I am a VERY active person and usually have the right amount of energy to get me through my day. lately i have been getting the right amount of hours of sleep. go to bed at 10 wake up at 7:15 - 7:30. I am slightly overweight but have recently had bloodwork done and everything is perfect. bloodsugar, cholesterol and thyroid are perfectly normal. like i said earlier, im very active. at one point i was doing 2 workouts a day about a month ago but now have rounded it down to one vigorous workout a day with the exception of maybe two a day once a week. working out is my passion i am also a trainer for many friends and family members of mine. Another thing to add is i was very stressed the past year with school but now it's summer and i feel very relaxed and havent been stressed for 2 weeks now. i do have a slight allergy to wheat and gluten which i know is known to cause some fatigue but lately its been extreme fatigue. my muscles are sore, i feel like just lying down if im out shopping. i was sitting on the couch and felt myself slumping down and trying to keep my eyes open at 7:00 at night! walking up the stairs was even tiring for me and usually i take two at a time no problem! this morning at the gym i was so tired after only 30 mins of cardio. i usually do an hour or an hour and 15 of cardio and 30-45 mins of weight training! i just would like to know if maybe there is something i could do to make myself more energized or if i need to get something checked out by a doctor? One more thing to add is i am 16 years old.