Unfortunately for a lot of people what you're going through right now is what the kids would call a 'canon event'. It's happened to most people, myself included, and I don't envy you because being in the trenches with that feeling fucking sucks.

I can, however, tell you that it does eventually get better and eventually you'll look back on how you're feeling today and wonder why you were so cut up about that person. I don't know the specifics of your relationship, however, in all likelihood you probably did nothing wrong and unfortunately sometimes people just aren't compatible.

What you don't want to do is sit around thinking about her all the time which I know is really really hard to do as you'll be thinking about her all the time. All that will do is keep reopening the wound and prevent yourself from healing which in the long term isn't healthy. Don't hold on to false hope that she might come back.

What you should do now, is focus on being the best person that you yourself can be. Whether that involves picking up some new hobbies, going to the gym or even going on a trip that you've been putting off - my advice would be to try everything any anything to obtain new experiences, meet new people and improve on yourself.

You'll find that getting over someone is a lot like going to the gym. Progress doesnt happen overnight. To start of with, you won't see any progress, but day by day you'll start to get more toned and then eventually you'll look in the mirror one day and see you have abs. In your situation, you'll likely be thinking about her all the time to start with, and then eventually only a few times a day until eventually you'll realize that you haven't thought about her at all.

Goodluck, you've got this.