That makes me sad :/ , it has happened to a lot of people , you should try to involve yourself in lessons and try to make friends that way , by helping or getting help of others I'm sure you will be able to get along with someone , if this isnt an option you should try try to boost your confidence , if you go to talk to a group of friends it may seem awkward at first but I'm sure you will find people you get along with , hiding away in the library will make things 10 times worse then they already aware, people will think that you are not looking to make any friends , it's all about how you portray yourself , be awkward and unconfident and you'll find yourself thinking everyone laughs and talks about you , but YOU never gave them a chance to actually know who you are , it's all about confidence you might find it hard to approach people when your at school but even if you stay in your common room I'm sure people will approach you , not everyone is as mean actually last they seem.
I was in your position when I moved to a new sixth form