Hun, it sounds like you are doing all the right things. However by 6 weeks she really should be above her birthweight. It doesn't mean that you need to stop bfing, but you do need to get that weight up. That meets the criteria for Failure to Thrive. How much below her birth weight is she now?

Sorry for all the questions, but how many feeds does she have in 24 hours? How many wet and dirty nappies in 24 hours? If she is sleeping for 3 -4 hours at a time all day, she probably needs to feed more often. Some babies can be very sleepy, and then because they don't feed often enough they don't have the energy to feed, and it all goes downhill.

I would suggest waking her to fit more feeds in, and try to get at least 8 feeds in 24 hours, at this stage more would be good. Once she gets some milk, she should start getting hungry and feeding better (and possibly sleeping less, sorry about that!). It might also be an idea to see your GP again, or an MCHN, preferably a bfing friendly one also.

GL hun.