Bob . . . I had the same trouble with my youngest bitch here re: phantom pregnancys. The first two seasons that she had were phantoms, second one worst than the first..... bagging up in her back teats even producing a little milk.
So before her 3rd season tried some of the raspberry leaf tablets from Dorwest herbs, and I believe it helped her no end, and as I write this she is in season again.
What I do with my bitch is give her 4 tablets daily mixed in with her food as soon as she starts spotting.