I really feel bad for you. Here's a list of comebacks that might help you:
Bully: *Any insult*
"Thank you for your good portrayal of a self-centered butthole in the movie of My Life."
"You should come with a warning label"
"Unless your name is Google, stop acting like you know everything"
Bully: "You're gay"
"What is this, a proposal?"
Bully: "You should commit suicide"
"Sorry, idea not found."
Bully: "You're trash."
"Well you're the entire garbage dump"