SHES TRYING TO STEAL MY LIFE

So there’s this girl that I was once best friends with we used to be super close until she lied on me to her mother and ever since then it was never the same now me her and my new best friend all have problems. The girl now copies all of my shoes, clothing, hairstyles, watches and the list goes on now she’s trying to steal all of my close friends especially the ones who are boys and it’s so upsetting because they are my friends that she didn’t even notice until she saw me with them like WHAT DOES SHE WANT?! She also sent threats in notes to my best friend warning her to stay away from one out very close friends that is a boy. We are currently working on that with a teacher but what to do about her taking my life?