Schoolx over and got girl problems?

Hey guys see i finished school two days ago and I like this girl and i never told her. wenever i talk to her i get self concius and feel like im gonna puke But when ever im not talking to her im tempted to stare at her Ive also Have been getting Fs in school since ive never talked to her i dont have her phone # There a way i can get her phone #? There a way i can practice not puking ?