Is this a friend? How should i defend myself if shes not there?

Maybe it's just me but i have a best friend, her name is Marykatherine. Well, idk if im just overreacting but i feel that she doesn't put in enough time into our friendship. She just started talking to this guy and slowly been pushing me away. Ignoring my phone calls, leaving me at the bar just to go converse with him.. etc. Meanwhile this guy she's talking to is kind of rude. Hes so open to his opinions, like "hey im not digging that shirt" or if i dont wanna go somewhere he says "dude dont be a pussy". Stuff like that sorta bugs me, but im too chicken to tell him something. Meanwhile, marykatherine, my best friend, doesnt say anything to me. But when someone talks bad about her or to her, i take up for her. Recently she was attacked by 2 girls that didnt really like her for no reason im assuming and i wasnt gonna get involved, but its my best friend and i wanted to do what is right. i would never punch a girl, but in a way i felt that i had to stop the fight somehow, so i pulled one of the girls off, and of course, some dude thought i punched that girl, so i took a few jabs to the face. But idc because thats my friend, id stand up for her. And lets say someone calls me gay. Marykatherine would just stand there, im not asking her to take up for me. but i would like her too, (i mean, i do it for her). Idk, maybe im exaggerating. can someone plz give me advice? or any quotes that may help me in life.