'Thing you are good at' is not your personality
As teenagers who have experienced life only for a short period of time, we may not have so many experiences. This can lead to one or two experiences becoming the focus of your personality. People may start defining themselves by their academic achievement, mental health or, like me once, exchange student status. This is a natural thing that occurs, and, with the problems it brings, also essential for character building.
You will go through an identity crisis when you screw up the thing you define yourself by. Be it by getting a low test score or not being socially known, there is an event in our lives which shakes things up. We are forced to abandon the focus of our personality and in doing so, discover new parts of ourselves. My personality was based on my academic ability a few years ago. After transferring to boarding school and messing up my exams, I felt terrible. Where my academic output dropped, I could try out new things such as dance and music.
I was lucky enough to have teachers that let me shift my focus. Unfortunately, many feel pressured to get back their old persona. If you had a ton of friends but you no longer do, instead of letting go of that aspect of your personality you may feel compelled to redeem it. You are likely to miss opportunities while overcompensating for a lack of socialization, which can result in creeping people out and a restraining order. In such a process you may not discover new parts of yourself nor successfully redeem your old self.
Consider it like an error you made during painting something. We panic and try to fix it right away, only to worsen the blunder. Let go of your painting for a while. Take a walk, speak to people, write and find inspiration that brings a new perspective to your painting. You can fix things by not fixing things for a while. If you are no more good at what you once were, relax.
This is your chance to find yourself. Imagine those who have been doing the same thing, living the same definition of themselves, because they never failed.