bullying?

yesterday I had a banquet I was having a bad night bc my boyfriend & I were fighting then I was having fun bc I was dancing with a guy friend who used to be a friends ex then she started tripping over it they haven't been together for almost a year she started talking shit about me with her friends & she called me a bitch I told our guard teacher & he didn't do nothing so I had to go home early 
I don't know what to do if it's bullying or not 
I have her for two classes & she is talking to some guy too I feel sad like I'm depressed 😭