Passing stool after each feed is normal in early infancy( known as gastrocolic reflex). The bowel pattern usually get regular after 3 months of age in most of the babies.
Better to give exclusive breast feed. If not possible due to any reason give Nan-1 in a proper concentration. Get a routine examination of stool and also for reducing substance to look for lactose intolerance
. Burp the baby after each feed to decrease gas related problem.
Be watchful for decreased urinary frequency, decreased feeding and any other problem.
If you notice any of these then consult your doc.