I recommend you start secretly taping these comments and actions, and then showing them to the police and to the principal. Don't accept this abuse. If you don't contact authorities against these "people", then the abuse will continue. PS. If they are doing this to you, then they are doing similar things to other people also. I hope you stand up for yourself, their actions are TOTALLY UNACCEPTABLE, ABUSIVE, AND ILLEGAL.
You could always tell them that you changed your first name, or actually do so.