So if someone called you a bitch, there are for two reasons.
1. They're joking around with you.
2. You totally deserve it.

If you've been called a bitch because the person who called you that thought you deserve it, then you should think why you deserve it.
Think deeply, why.
And improve.

Not calling that person a bitch back.

"I called you bitch in front of your face. Because by that, I hope you can open a bit your mind. Yes, I was harsh. *emotionally-driven" Am sorry.
But you. You called me a bitch behind my back. And that's rude. And you're still pretending so nice and all in front of my face. Sorry, but fuck you!"