I knew of a Dalmation who used to have false pregnancies all the time - owner thought it was "cute" when she did it.. she was never fixed, but also never bred (by her anyway) I'm sure she was bred in her previous home(she was a rescue).
Anyways, you could give her a tiny toy to pretend its her baby... that might help sooth her nutering needs.
Thats what happened with the Dalmation - she'd carry around a few toys and pretend they are her pups.