How can i stop obsessing about my crush?

[Stranger]

I dreamed about my crush every single night , i already told her i love her and then she said ' we should be friend instead of that ' . So I deleted her facebook so i can get over it but she added me back again :< . Right now i guess it is getting worse because she is not only appears in my dream , now when i go out have a break , everyone with ponytail hair looks like her to me . it makes me feel so depressing when i meet ponytail hair's woman