you should call your pediatrician. the two things (jaundice and blood in the stool) could be unrelated but any time a newborn exhibits unexpected symptoms it's a good idea to investigate them. if your baby has decreased appetite (not nursing as much or as often) or is not wetting a lot of diapers each day then you should go to urgent care. babies can become dehydrated very quickly which can make any other problem that much worse. pick up the phone and call. wishing you well!
newborn was treated for jaundice and now is passing blood in stool.