why do I feel this way, whats wrong with me? :( and how do I cure it?!

I never have strength, or energy. Its not like im lazy, or want to sleep, its a different type of tirdness. I feel like I am just a floating cloud, with no aim in life or anything. Days turn to months and months in to years without me realising, because im always doing the same routing and busy with family that thats how my life goes. Sometimes its like im in a coma, or that im a robot, or existing but not living. Sometimes its like something causes me to snap out of it and wake up, and thats when i realise 'where have i been?' and i think i'm nearly 22, and i think of where did the days and months just go by? I want to do so much but even the small things i never seem to get round to doing, and i always feel I cant because i dont have the energy for them. Its almost like i walk with my eyes closed, everything seems just a dream and hazy.
I know it sounds crazy. Any ideas? thanks