creativity?

I've always wondered how one becomes creative. I, for once, didn't really consider myself especially creative-- I always look for guidelines that will thereafter frame whatever it is I am creating. Until one day I came to the realisation that all I needed was confidence and trust in my ability to develop something.

Having that as a starting point, I started adding my own feelings and thoughts to the process. So: self-confidence + heart + brain = creativity

However, this also presents a problem: when it comes to writing, emotions play the biggest part. My most treasured writings were given light when I was falling in love, when I was hopeful, happy, horny. Whenever I'm down I write, but it never fills me up-- you see, when I notice I'm sad and depressed, it's as if everything that comes out is strict, blunt, real, but in no other shape than the one it already has. It's nothing new, just a reflection of constant depressive moments. And I feel like I can't create anything or write about something other than myself; I'm blocked and can't even make a metaphor or play with words.

So I guess the question remains and I'll also keep waiting for its answer. Someone?