As you milk supply decreases, often your let-down reflex will be much slower as well. I have really noticed this with my own body in the last couple of months. Babies quickly figure out which side takes too long for their patience, and they will sometimes start to favor one side. I have actually only been nursing on one side for months now as a result. DS kept rejecting nursing if I offered the left side, so I would go straight to the right, and he went back to nursing. But I can tell he is weaning too. And there have been many a teary day here! I totally 100% understand you on feeling devastated. You are not being silly at all. It is a hard process of letting go of that very special, unique bond between you and your baby. It may not be over yet; he may still come back for awhile though. Hugs to you!