Why are Sagittarius intimitated by?

Im Gemini and yes i agree. when i first came to highschool my Sagittarius ditched me for some other girls and then when she saw i made friends with these popular girls, she got soooo mad. and dont get me wrong, i still wanted to be her friend. but nooo, she started hating me for no reason at all... but now, shes like NOTHING to me :) she hangs with these so called 'popular girls' now & all this time she just wanted to be popular lol.