Don't her all depressed over a guy (or a girl) from your past. That's like being sad because the garbage man picked up the trash. ---Not saying they are/were trash, but saying it is over, do not dwell.
20 things to live by. Love this! You don't have to listen to how other people want you to live your life. Live it your way. Do your things. Make your own mistakes. Live life for YOU while you still can.