Take this time to really evaluate the realtionship. Okay, so you have only been dating officially for three weeks. But maybe if you take a look at it, possibly you were doing some things that could be scaring her off? You say you don't have a soul after this. You didn't possibly rush in shouting "I love you, I want to marry you" did you? That can scare anybody off if you aren't letting things progress naturally.
She can't really appreciate you until you are gone. Don't talk to her. About anything. Even if she contacts you, you shouldn't feel like accomodating her when she is flip flopping all over the place on this. I don't know many people that really survived a break. It's a nice way to tell you she's dumping you and she feels guilty enough about it to cry and tell you how much of a good person you are. But no matter what she says, her actions told you she doesn't want you in her life. I think that says enough.
Be strong. You can only get shitfaced for so long. And this better not include blackout phone calls/texts. You are going to miss her when you come out of your alcohol induced oblivion, and you are going to have to have a little strength to get through this without her. Stay strong, keep busy, vent to non-mutual friends, do whatever you need to except contact her. If this is what she wants, this is what she gets.
Waking up next to a beautiful girl,
Step outside and say hello to my beautiful world.