Fear of dying young

I went through a traumatic experience this year and i realized my own mortality. Even when talking about my plans, I will say "if i'm still alive at 20, i'm going to do this and that....." . i am 17 now. I believe that i have a high chance of dying young and that scares me. I see life as utterly pointless and sometimes i think i'd be better off dead as soon as possible so i won't have to deal with my fear and negative thoughts any longer. It's selfish, those who know me are gonna be devastated if i die so of course i'm not going to kill myself. I don't want to. But still I think i have a very negative outlook on life and i don't seem able to deal with it at the moment...any advice?