Why did I lose so much energy?

I am known to be a very energetic person and i used to always have energy, but since August started (and volleyball season started) i am just always so tired, i have no energy. I thought it would be gone once volleyball was over, but it hasn't left.I never cared if my hair looked really good, i used to loves sweatpants, but now i am so concerned with my image. Does anyone know what is wrong with me, or how I could get my energy back?