Need help with this girl i know?

Theres this girl i know in my homeroom in high school and i talk to her alot and make her laugh alot. shes very pretty and very cool.....but she has a bf....i still talk to ehr alot but i never flirt with ehr now one of my friends told her i liked her i mean i do but i didnt want her to know that sooo now she doesnt talk to me anymore or laugh at teh things i say as much what do i do?