A bully keeps calling me gay and fat. I am looking for a parent answer as to what I should say or do?

We were in track conditioning (guys on m,w,th girls on t,f) and he told me the only reason I was there was to look at guys. And I could not stress it to him enough that I am not gay. I have a girlfriend for crying out loud! Then when were doing running drills and he was making fun of my fat. I am trying to lose it but it just wont go away so that wont stop it. I don't want to be "that kid that tattletales" and tell an adult but I also would like it to stop. Any suggestions? I am