I feel weird? About relationship stuff?

[you dont need to know]

There is this girl i like ALOT and shes nice shes funny and her friends all said she liked me so i asked her out she said sure but later said she was busy and the next day her friends told me she doesnt like anyone anymore? What did i do wrong. Im still in love with her and im going crazy. I went from do you think shes thinking about me right now to crying to do you think she thinking about me agian in like ten seconds
Bact to crying a feel like im gonna throwup