I gave my last breastfeed to 12 mo DS a week ago, having gradually cut down over the past month. Was all going fine, but now my breasts are really painful. They're not engorged at all, and I don't seem to have any blocked ducts - just really, really sore! Is this normal, or should I be worried about possible mastitis? I've tried expressing a small amount, but doesn't seem to be doing any good. How long is this likely to last?