Firstly, you're doing such a great job with your new little bubba...and in the early days there seems to be so many uncertainties. I was always told you cannot overfeed a breastfed baby. They regulate the milk supply themselves and will feed until they're finished.

At 4 weeks their digestive system is so new, so wind, vomit and runny poos, even green poos are common. I always went by the rule that my baby has a relationship with my boobs that I am not a part of, so I just let her suckle for as long as she wanted! You cannot control how much milk your baby is sucking at each feed either. Some times she might suck vigorously and take heaps of milk quickly, and other times she may be sleepy and drink slowly...

As the ABA would say...ditch the clock and go with the baby...

Hope this helps.