I'm sitting on my bed and she's packing all of her stuff from my apartment as I type. Tomorrow she'll be gone.
/adv/, should I stop her?
Go speak to her, tell her you are fine with her leaving as it is her choice. Help her pack, help her decide what she wants, assure her you'l get the rest of her shit to her. Make sure she takes none of your stuff.
Actually going out on a good note does no harm, plus she may actually decide to stay if she realizes you can be so cool about this shit no matter what you have both gone through.