I'm sorry you have to interrupt your breastfeeding, it is heartbreaking in a way only a mother can understand and I know what you mean about the smell... I'm not going to be all logical here, you've probably heard it all and it doesn't matter. When your baby is being fed by formula and not your precious breast milk it is really upsetting. Just know that you are not alone in feeling this way. And yes, pumping is poo!