KIDS ARE ALWAYS BULLYING ME?

I'm a 14 yr. old girl in middle school who's always picked on in middle school for no reason at all.I'm very shy and come to find out most of the people think I'm stuck up because I'm so quiet.Now don't tell me try to be more outgoing because I do that a whole lot now and people or even meaner.I always wear pretty accessories which I notice makes them angrier with me.They mainly call me ugly,dirty,ect.I don't know why they hurt me like this when I'm so nice.I tell the teachers and they just accuse me of being a snitch or tattle-teller.I'm so tired of hurting and crying from torturing days at school for no reason and my parents don't understand.CAN YOU PLEASE HELP ME?