Broken into pieces.

You realize you are never going to fully forget about her. No matter how hard you try, she's going to come into your memory every now and then.

In the first few weeks, its ok to be depressed because you feel so numb and lifeless. Try playing some sports to see if it can distract you.

after you start getting your thoughts back together, write her a letter.

Pour your heart out. Write to her about the fun times you had about what you liked about her and blah blah blah. The purpose of this letter is to simulate an actual farewell conversation with her, since fone is a 2 way conversation and you never really get to say what you really mean. Letter is the best!
And in the end request her to burn your letter. It doesn't matter if she does burn it or not, for you, its a way of parting with your love and tying up loose ends.

Then buy yourself a bottle of gin, another of tonic, couple of lemons, salt the mothertrucker and drink yourself silly. Its ok to cry. Real men have real hearts, those who claim not to cry are the fake ones.

Lastly give yourself a pat on the back and congratulate yourself for being lucky enough to enjoy her company during that specific time frame, which she could have spent with anyone else.

There is only so much you can do, the rest is upto fate.

Take care man.