How do you get your bestfriend back?

i feel really bad and i was stupid and my other best friened was her enemy and i was being super mean to her bec she was goin out wit a kid i really like and now i feel horrible bec i always thoghut of her as my bestfirend not da other gurl n now i tlked so much shyt about her nad her stupid asz is hanging out wit my other ex-friend wich is a and i fought her n SHE WON n dey woodnt even noe each other if it wasnt 4 me so w.e. n now her stupid az is saying she is a bi too n i feeel really bad n i miss her n we were so much good friends n we did so much shyt together n had so much fun wen we were bestfreiedsn n omg i just want her back ='(