I just broke up with my boyfriend of 6 years, and it feels like your world has ended. After experiencing painful breakups with the same person, I understood that the only thing that will ease the pain is time. It is hard to leave it to time to heal when your every minute is painful. But you will grow out of it. If you think that you can do something to get back with her, try it now, not later. But if you also think that it is over, then wait with patience. KEEP YOURSELF BUSY. Focus more on your PhD. It is harder than ever for you to do that now but just think how cool and great it would make you feel like if you could take this negative situation and use as a source of motivation and determination.
The things will get better. You will look past and be happy with what you achieved so far.