Why am I always the burden or an outcast

All of my life I’ve been depressed but never really knew it till I was 16 and got diagnosed with chronic depression. For years Now I haven’t had anyone. No one to talk to, no one to ask for help, or no one to be with at all. I am completely alone. Even before my diagnosis it wasn’t any better, I was the kid on the side tagging along that no one wanted. I was a failure to everyone around me, I would constantly get asked why I even bother doing things, or why I even tag along with people. I never had an answer for them until I realized they were right and from then on I never talked to anyone, but now there isn’t even anyone to try talking to. In this past year it’s really been getting to me; so I reached out to everyone I knew. They ignored me and didn’t even bother responding to me. No one even remembers me anyways. I never once did anything exciting or made people happy. I just can’t take being this alone anymore, it leads to me frantically searching for sharp objects to hurt myself with, or Many hours crying in my bed. I just so desperately want to be with someone now I don’t know what else to do. I’ve become so numb to where the point that I lost touch with my feelings and I have to try really hard to express emotions and such. Because of the nature of this I can’t take compliments or encouraging words serious anymore, they just lost all their meaning to me. All I have to talk about is my depression and no one wants to listen to that. I’m tired of living like this but I don’t what to do, I just can’t even help myself right now, how could I possibly help other people and have a good relationship either intimately or just for a friend.