I agree. Sure, sometimes things happen and therefore maybe, just maybe, she wasn't able to contact you while away. IMO, even if this were the case, I would think she would be jumping at the first chance to come and pick the pup up after getting back.
If your instincts are telling you that something is up, then you should trust them. There are plenty of loving people out there who would love to give your little pomchi a wonderful and loving home. Keep us updated!