I know this is cliche, but find the pieces, pick 'em up, and keep walking. I had an ex do the same thing.
If what you do is fairly brainless, use it as a form of meditation.
Set aside a time to truly reflect on that relationship. I'm not talking 20 minutes. This may be an all nighter. Go through all of it, the happy times, the sad times, the rough times, the good times. Reflect on how she changed you and how you learned from each other. Allow yourself to feel as you go through it, to cry, get enraged, smile, and laugh. This will go a long way towards helping the healing. You may not be far enough into your mourning to do that though, so that call is yours.
Let it out as you can. A soul in pain can only fester if not allowed to breathe.
Find reasons to smile and laugh. Beg, borrow, or steal funny movies and books. Get lost in enjoying things you couldn't while you were attached.
Your heart will heal, eventually. I can't say when, but you will love again. One day you'll wake up and she won't be your first thought. One day, she'll be put aside in a special box in your memories and filed away. For now, let yourself process it.