[Cincilator]

Hello there. Well my question is to know whether i am getting bullied or not. And I want you to say things that would make me feel better and what to do.
(NOTE : I've been taking the anti-depressant lustral, for 2 weeks now, just started)

So In school i have a group of close friends, i have my best friend in that group too and he is a great guy. Anyway We are 5 friends and chill/hang out together in school. Well There is this guy in our friend group, he is known as the "joker" of the group because he is really silly and all that. He talks a LOT etc. And the weird part is, sometimes he puts one of us down, and make fun. Not just me, he puts some of us down all the time when he is bored. He says stuff like "fat,gay,lol wtf is he doing what a idiot retard" stuff like this.

None of my friends stand up and say dude stop putting us down.. what a bitch.. So One day I decided to do it. I stood up when he said "go fuckyourself fat retard". I asked him to stop doing and saying stuff like this, i asked him to stop putting us down. WelL he said "lol, you are being a little girl again.." ( NOTE : He has been taking anti-depressants for 1.5 years, he was depressed once ago )

Sometimes he is a great guy who you can talk with. He kinda differs from others, he knows more about the world than others and we have a lot of fun chat with him. But whenever he gets bored a bit (or whenever we meet up with other friends ) he starts putting someone down. But actually he is a good guy that you can talk to.

So am i really being a little girl? Or is he really bullying me? Please answer me. As I told you I'm the only one between my friends that takes these insults serious, so i stand up and ask him to gtfo. But I always get the same response : Stop being a little bitch.
Am i seriously being a little girl? Should i stop being friends with him? What should i do???