You matter, you may not think that you matter but you do, you're important. you can have an impact on somebody's life that makes it better for them and you get the satisfaction of making their life better.
if you're thinking about suicide ,don't do it. Sure it's an Escape From the emotional hell that we call Earth, but it doesn't just affect you it affects everyone who cares about you any friends and/or any family that cares.
*If you started having depression AFTER* Find someone that understands you, someone you can talk to. If you can't find one of those people in the real world you can always talk to me^^