Hello, I have cried almost everyday for three years due to a failed first relationship. And it is affecting me horrendsly. How can I fix it?

Positive thinking. I think you should realize that you are very young and you have your whole life ahead of you. The best course of action is to ask yourself to think positively and avoid making negative statements about it. Instead, make positive comments about the future and your future relationships and catch yourself if you ever do the opposite. Good luck.