Am I Depressed? How would you be able to know?

I'm not sure if I am depressed or not.... I'm always angry... i lash out for no reason.... i start to cry for stupid reasons... for instanste one time i started to cry becuase my meatball sub was too messy and hot. I want to kill myselft sometimes. I hate life. Im starting not to trust in God anymore... what do i do and i how do i know...??????????