Tricanda, wow what a athletic event to accomplish so soon after birth and breastfeeding too. Let your body do the ruling on event day. Your training time should give you an idea how your body will react. As an ex-breastfeeding mom I know mastitis is nothing to fool around with. Very painful for you and baby would not be a happy camper. Definitely as always push fluids, and warm packs and showers if breast engorge. Good luck.