Do you stay up late browsing the TV channel or surfing the net when you have work to do in the morning? Do you get worked-up on trivial things? If you do, then you are expanding your energy needlessly.
Energy is not infinite. No matter the supplement you take, the human body cannot perform its best after a certain point and completely breaks down if you ignore the warning signals.
To perform at your optimum best, it is important that you expand your energy at the right things. Avoid things and people who suck your energy for no good reason.