
Certainly take all her toys right away. If she nests, then you may have to take her bedding away too. Phantom pregnancies are a perfectly normal condition in bitches, and almost all will have them to a degree - some will have almost no symptoms and others will go the whole hog and be really miserable.
Basically don't give her time to brood but keep her busy, cut down the amount of protein in her diet and give her loads of exercise.