I feel your pain Dinah,....my best dog Belle had crazy heat cycles that were never on time, no telling when she would come in. I got tired of dealing with it and had both her and Abby spade. Good thing I did too, when I went to pick Belle up, my vet, who's a friend of mine, said it was a good thing I brought her in,.....she had a really bad case of endometriosis, so all is well that ends well I reckon.
Did they correct the problem? Ive never heard of dogs having endometriosis.