I'd check with my HV too. I breast fed all 5 of mine and their poo was bird seed yellow until I started weaning. In a healthy breast fed baby, the poo shouldn't really be offensive at all.
Breast fed babies can get bad wind and colic symptoms if there are not latching on properly though. Is he feeding well? Is it commfy when he is feeding, or painful. Ask to speak to a breast feeding counsellor if you feel you are not latching on properly.
Also, are you on medication/anti biotics. Sometimes medicating mum's can produce funny poo in a BF baby.
My hunch would be the same as Andy's; I wonder if he has a mild infection???
True about the Jaundice too.
Take it easy, and remember to be kind to yourself.