I don't know what is wrong with me, please help me? :( (this is short)?

Hey, i'm a junior in highschool and for most of my life i've felt the need to be better than what i am. The urge is constant, i always need to look prettier, be more outgoing ect ect. I never meet those standards i put myself up too. I honestly feel like a failure and that i don't desercve anyone. I see my friends having fun and talking to a bunch of people and it makes me jealous, i seriously wish i could be like them but everytime i try to be more outgoing or talkative, people don't notice me. I hate who I am. If i sound like a whiny teenager, im sorry but i would never ever talk to anyone about this, and i really need advice because I can't stand feeling this way anymore. How do I get rid of this feeling?