Why does my reality change from day to day?

Example one day ill feel really good about things and feel on top of the world like things are working the way theyre supposed to, then the next i feel totally absolete from the world and like my life is going down the drain...or sometimes i dont even really feel like im me anymore like im out of touch with myself and reality no im not knocked up on drugs, thank you maybe a lil green here and there but hey people experiment, I just really want to know how to liberate myself when out in public and really be my true self and feel good not having to act a certain way to get a certain reaction back, if that makes sense. Help, any input on this would be greatly appreciated. thanks