How can I stop being sad?

Some stuffs been going on lately. There was this boy who was just like me. We fell for each other. He asked me out. I said no out of shyness. Then he changed. Now I see her falling for my old friend. And my best friend is moving. We've been friends since I was 7 and i've been feeling so depressed because the government is taking it. I learned that I'm not as a good a singer as vie been told. My grades are so bad. My moms been so angry at us. And vie lost most happiness. Can anyone help?