Can someone help me think of something to say to my parents...?

I've been depressed (I think it is depression) for a while now, and I Can't take it any more, everyday is a constant struggle inside my head. I am fine one minute, then I just start crying. I stay up all night and sleep all day, so my parents don't see. I keep thinking about death and It's driving me mad, Sometimes I'm thinking 'I don't want to die, next I wan't to kill myself. So I need to get help but I don't know what to say to my parents. We are kind of close but I don't usually talk to them about personal feelings.