See you think all these things because you lack confidence in yourself when in reality none of it is true. You are your own person, you are simply amazing and you should NEVER let anyone make you think or tell you different. No one is better than you, in my eyes everyone is equal.
Many people feel shy when they meet new people, or do things that they don't normally do but there are many ways around it, You don't have to suffer.
Shy people are good too! Not everyone wants loud, outgoing people all the time. Imagine our world if no one was shy/quiet, everywhere would be loud (which can be a good thing too).
The point is YOU ARE BEAUTIFUL. You are your own person, you have your own body and mind. You don't need to do things to fit in, because other people do it or because you are told to. You are your own person, you can do your own things, you do these things for yourself not for anyone else, you don't need to think about what other people will think, it is for you and you should do whatever makes you happy because to be honest that is all that matters. Be yourself.
So starting tomorrow keep your chin up when you are walking through those corridors or through crowds of people, When you hear people laughing behind you, think to yourself 'I AM ME AND I DON'T CARE WHAT OTHERS THINK AS LONG AS I AM HAPPY'. When you meet that new person gradually ask them questions so that they do more of the talking. If you need more help then talk to someone you trust.
BE YOU, KEEP YOUR HEAD UP AND DO WHAT MAKES YOU HAPPY