A girl that I used to have a math class with works at my gym. She asked me out but I said no.

She then proceeds to talk shit about me and spreading lies witch lowered my SMV tremendously in school because she was a popular girl.

She then turned to my friend and went after him in order to make me jealous and it worked.

It bothered me for some time but I came over it. She left him as soon as she saw that I no longer cared.

The problem is that she works at the gym I go to and it's fucking awkward. She doesn't say hi and I don't either. She glances at me sometimes but I ignore it.

Tried following the rule= Don't shit where you eat.

What should I do?