Hi T.,
My BFed baby only pooped once every week to week and a half. On the days he did, it was a whole-day affair. It started out as being many times a day and at about that same age as your baby, it changed. At this age, the digestive system is just more mature.
This is perfectly normal. breastmilk is perfectly digestable and the bowels behave differently than if the baby is getting other foods. Please do not give your baby a suppository!!! This can be painful and harmful to her. Some bfed babies poop only a few times a month (like mine) and they are just fine.
Nature created babies to be able to communicate with moms when something is wrong. She has no symptoms of ill, it is just a new behavior. She is perfectly fine.
If this is the case on formula, however, you should push extra liquids and consult your pedi.