You're a teenager is the problem. You have hopes and expectations but other people just don't measure up so you feel bad about yourself. You shouldn't as it is they who have failed, not you.
Take pride in yoiurself and don't lower your standards to be "one of them". As soon as you do then your life is always going to be on their terms. You responding to them and feeling bad when they fail over and over again.
Forget about all that, think through what you think you are, as a person. What do you think about, what do you really want and how will you achieve that. Don';t be dragged down by what others do and say. Most of them are failures and they want you to be one too. Rise above it all.
And the most obvious thing to do is see a doctor and get referred for therapy. Talking this stuff out is absolutely the best way to resolve it and come out as YOU. Do not expect the therapist to tell you what to do. They will help and guide but it is you who must find what you are and want and then find out how to become that.
Today I am totally confident about me and the rest? That's up tyo them. I do things my way and hope they can meet me.