What is "It"?

Why do i call it depression if i don't even know what i'm feeling? How can i be ok and in the next minute not? How can't i be excited about anything? What is wrong with me? Is it depression,? Is it anxiety? Does "it" have a name? Well, should it? I don't know whats going on in me... Seems like "it" has taken control of my body and started to run it insted of me. All i get to do is sit and watch. Watch everything i built ruin in front of me, everything i liked becoming boring. Every single color arround me become a cold and hard grey. Not black or Blue. Those colors still have some personality. Grey! So thats what i am doing. Sitting and waiting for it to end, one way or another...