People's opinions, especially negative ones, largely stem from what they know they don't have and can't do. You eventually have to stop basing your self-worth on the insecurities of others.
“Teenage years are often years of insecurity, of feeling as though you don’t measure up, of trying to find your place with your peers, and of trying to fit in. You may be tempted to lower your standards and to follow the crowd in order to be accepted by those you desire to have as friends. Please be strong, and be alert to anything that would rob you of the blessings of eternity. The choices you make here and now are forever important.”