Why does my energy crash

Will power, the mind heavily depends on how powerful is your will, depression is a very powerful agent to naturally fight... but being around energetic and happy people can make you powerful :) but to start finding such people you have to at least try and act being powerful and energetic around people "always" be a beacon of hope for others.. and they shall help you .Physical elements can help such as "fruits" Vitamin C, B1 and B6, and D. play the essential parts.. Drink more natural 100% Orange juice. eat less bread.

This doesn't necessarily mean you have depression,but i think you need to have blood test done as you could have a number of things doing this.
You sound a little like how i was and my issue was that i was low in iron.Its best to see your doctor,tell them how you have been and when it started etc,so you know for sure where to go from here.
Self diagnosis is not what is needed here,so please ask your doctor to do blood tests.He will check for many things to see why this may be happening to you. Good luck!