My baby is only 10 days and unfortunately I have mastitis in both breasts. I started erythromycin yesterday for 14 days and was told by the doctors that only a small amount would pass to him. However, last night he was beside himself and had a bit of an upset tummy which the doctor warned me about. He has had some formula and I'm now thinking of continuing the formula for the next 14 days and expressing my breast milk and ditching so I can go back to breastfeeding after. Has anyone done this, is it possible? I cannot see him in the state he was yesterday again. It was heartbreaking.