My "bestfriend" hates me. Shes a total B**** but i need her?

me and my "bestfriend" played on the same travel softball team for two years without problems. we went to different schools but we were best friends.well this year we started going to the same school and it started going down hill. well we played volleyball for the school together and she just started getting an attitude like we would do a drill and i always never did it right. but she apparantally did. then when school started ill admit i would branch off and try to hang out with other people cause i was new ya know? well i guess shes been holding an on and off grudge all year. half the time shell roll her eyes at me when i talk to her and pretty much humiliate me in front of the whole cl cause she has better comebacks than i do in our fights and she knows it. shell pretty much just be a total b**** and she doesnt try to hide it. the other half of the time shes my bestfriend and were crackin jokes and we love each other bla bla bla. but today we were sitting in study hall and -long story short my ankles broken and we were on the softball team but i cant play and my mom wont let me go to the away games or practices cause she wants me to come home and prop my foot up- we were sitting with like, 8 other people including my boyfriend, and she doesnt even look me in the eye and says "are you coming to the game today?" and its an away game so i cant and i say "no i cant my mom wont let me". this is her "well everyones gonna be pissed at you" me "well idk what they want me to do about it. my mom wont let me i wanna be there" her "well they dont know that and theyre gonna be pissed at you" me "well they can shut their mouth cause theres nothing i can do about it" and by this time we were pretty much yelling so our whole table was silent and listening to us and she was like "well dont get pissed at me. im just ssaying" and i said "well youre acting pissed at me so im gonna act pissed back" and shes like whatever and walked away, like out of the room and she didnt talkk to me all day. it was embaring. she also makes little comments that embarras me and just eat awway at me like my friend that i havent seen in forever was talking to her boyfriend and i was kind of zoned out but i was gonna go say hi so i took a step and the realized that would be rude while she was talking to a guy so i stopped then my "bestfriend" basically yelled "gosh dont be a ." i so badly wanted to punch her in the face. it was so humiliating and the next day she wouldnt let me sit by my boyfriend at school cause she wanted me to sit by her. and she called me a block. it just freakin eats away at me and gets on my nerves. not to mention she likes my sister more than she likes me. were 14 and my sister is 18 and shell run around with her and theyll leave me behind. but i know she gets on my sisters nerves and my sister just tolerates her. i know youlll just say forget her but shes the only real person at this school and at the end of the day i still love her. i never have these problems with just me and her but when anyone else is around this is bound to come up. and if i try to talk to her shes the kind of person thatll roll her eyes. so please please help me so i can stop crying.