I can't empathize, and I can't really sympathize either. I don't want to pity you in any way, but this work does make me a bit upset. Death is something that we all have to face. No one can escape it's grasp, no matter how close or how far you are from slipping through death's vale. Oblivion is inevitable, yet there are ways of making the wait longer.
Please, don't think that I'm trying to act as if I know what you're going through, or that i can play God and save you single-handed with a single piece of advice. No, not at all. I am in no way God on Earth and I can't tell you exactly what you're going through, because I don't know. I'm not even going to try.
What I can tell you though, is that (WARNING: this is going to sound incredibly cheesy and, or fake, so brace yourself) you are not alone. You probably know this already, (or, at least, I hope so) but there are plenty of people that can truly empathize with you. It's sad, but true. There are also plenty of people out there that you could vent to, and just have them listen, or be your shoulder to cry on or whatever you want really. Whether you find them, is a completely different thing, but let me tell you, just in these comments, there are already at least a few people here that you could talk to (myself included).
I don't know if what I am saying is helpful in any way, and I'm truly sorry if it isn't. I just want you to know that you don't have to have that dance so soon. You really don't have to hear the music, at least for a long time. Life may suck a lot of the time, and don't we all know it, but even though none of us here have the same story, or the same outlook on life, we can still try not to be dicks to each other and try to help instead. Go ahead and vent to/on me (terminology AKA a royal pain in the arse) or anybody else who has lent you a helping-hand of sorts, if you want.
Please, just let someone or something be that Kindergarten teacher for you. Do it for those of us who care, no matter how little we know you or how little you or anyone else cares. Do it for the sake of your future, or for people that do or will need you, or whoever or whatever matters to you and that will hopefully make you determined to try to block out the music, and to keep the dance a little farther away. Your life, and your time here may be small, compared to the rest of the history of the Universe, but it is more precious than the rarest element. Never doubt that.
For me, I love almost nothing more than to look up to the sky in the dead of night and see the trillions of giant balls of gas floating about in space. Each one of those tiny, little shiny dots in the dark sky looks tiny, and insignificant. But each one is huge, and unique, and beautiful, and just so, so much more significant than one might think, because without that ball of fiery gas, the entire universe would literally not be the same. Some may not give a flying crap about that missing ball of gas, but there are always those who do, because they, we, realize just how important it is. That single ball of gas could have gone down in history, it could have been the reason for so many important discoveries, and it could have been the very reason for life, no matter how small and short-lived that life may have been. I look at the stars, and that is what I see; the most precious artworks ever to have lived. I look at the stars and I damn well swell up with pride because I am a part of it. I am a small, insignificant part of the best thing I could ever think of; the universe.
So are you. So is every one else. Whether you've already died, are living right now or are yet to take your first breath of life, you are a part of something so much more. Never, ever think that you won't be missed, or that you aren't good enough, that you don't matter. That you're too stupid, too ugly, too hated, to invisible, too smart, too whatever, because you are not.
I'm not saying that you have a happier life than you think or some crap like that, I am only telling you a fact: you matter. You do not deserve to die.
Please, just try to live a little better. I know that things like depression are a mental disorder, and that you can't just "be happier", or "think proactive". You just can't. However, you can get over a crappy, ever-present mental disorder a lot of the time if you just do things right, like finding things that make you happy. Just look at Robin Williams. His death made the world cry. Depending on who you are, your own death may not be as big to the media, but for every person that sheds a tear for you and the rest of your life that never got a chance, it might as well be the world.