Today a friend came to me bawling her eyes out. The reason- the guy she liked started dating someone else. Well sister, let me tell you a story. I liked a boy. Its one thing to see the guy you like date someone else, but it's another thing to see him date a girl, dump her, date one of your closest friends, dump her, and then date your arch nemeses. All the while you are friend-zoned and he comes to you for 'dating advice'.
Well the point of my story is that it gets better. Don't worry. Right now you're feeling as if the whole world is shattered. But in future, you'll probably look back and laugh and how did you even like the guy.
You'll be fine probably get a new guy, I can't guarantee it as I haven't found one, but i guarantee you will get over him. There are plenty of things to worry about like global warming, poverty, etc, so don't worry about this. Stay awesome.