How can i stop feeling depressed because i know this girl will never be with me ?

I have a crush on this vietnamese female singer and she is very beautiful and i love her beautiful face. I've recently searched her on face book and it looks like she already has someone else. She is not very popular known but she is popular in the Vietnamese community of the united states. I get heart broken every time seeing her face because i know she has someone else, what could i do to make myself happier ? There is like nothing left in the world. I'm 19 years old and i have never dated and no one likes me so i kinda got infatuated by this singer because she is so beautiful.