Why has my friend changed so much and now dislikes me?

hey i've had that happen to me tons of times and people do change and shes probably doing that because she thinks that she deserves better and stuff and trying to become popular sense its a new school type and stuff but i would just forget about her she doesn't deserve u if shes gonna be like that don't txt her ignore her don't make it seem like ur desperate for her approval just don't care