Should i be mad or am i jus crazy and super sensitive?

ok there is this girl who i could use to call my bff but since we r in different classes we dnt see eachother as much.Shes in the smartest class were all the awsome people i love and i actualy can talk to those people but in my class im not saying ther stupid ther realy lazy and i dnt realy tlk to them but the point is we dnt see eachother as much and she doesnt care about me. OK i knew her since kindergarden shes always done mean things lke tell my crush i like him and embarrass me any chance she gets. and if im mad i usualy say im sorry for being mad at u .But this is when i got mad when our 8th grade field trip came up i was mad before bcuz she hit me in the face bcuz i was playing around with her and took her shoe bcuz she waz screaming and being obnoxious, she said sorry but she said its not my fault bcuz u took my shoe and i wasnt playing around but she was bcuz she was laughing,and then i was lke is tht your apology giving excuses for yourself and she said shes not, ther facts and i said i dnt like you and walked off.Later tht day she cried im suprised she did bcuz all the other time i get mad at her i say sorry for bn mad at u.But then its the end of 8th grade and its the 8th grade field trip and i forgave her bcuz i thought we wer true friends and i was over reacting and didnt i wanted to spend time with ppl i love so i forgsve her and then she ditched me.Since i knew her so long and we went through alot well i mostly helped her get through things dnt think she realy cares but the field trip is about havn your last moments with ur best friends and she hangs out with a huge group of peeps mostlyfrom her class and i kinda got stuk with ppl i didnt realy lke hanging out with and i kept tx her and when i ate lunch she was eating at the same place and yelled you cant sit hear bcuz im hanging out with them and theres no room for you and she totally excluded me the only person who cared when she cried when everyone hated her and she repays me by doing tht and my other friend tht was with her persuaded me to go bcuz she didnt want to hang out with the grl im mad at and then she ditched me to and didnt even ask if i could pull up another chair to sit but i guess i over estimated them and then the grl i known for a long time said i had to leave bcuz i couldnt jus ditch them to ahng out with u and i said u didnt i could hav came with u and she said then it wouldnt have been an even number for rides and i cant believe she was actualy telling me this bcuz what friend would and i realy was looking foward to hanging out with them and she ditches me and isnt even sorry am i sensative or am i acting lke i should bcuz she said im making a realy big deal about it