Am starting a new topic, as the board won't take my response to your question, for some reason, Minkyjj. The system just 'sticks'.
Hope NCT got back to you by now.
I diagree with some of the reassurance here (I am an NCT bfc). I think you are right to be concerned. It is not normal for a baby to be grouchy and grumpy all the time, and green poo can be a sign that bf can be fixed to make thiongs go better (green poo can also mean nothing, BTW, but coupled with the slow weight gain and grumpiness, it does add up to a situation that needs some attention).
It may be your dd is not feeding effectively, maybe because she needs to be positioned at the breast in such a way to get a good mouthful and stimulate a good let down and a good supply. This also ensures the baby gets the creamier milk (hindmilk) - the milk gets creamier and creamier as the feed progresses, which satisfies the baby and helps the baby grow.
A bfc can give you info on this, and help you decide how to position the baby.
Feeding often, and effectively, is the best way to ensure a happy baby, nice yellow poos, and appropriate weight gain.
Hope this helps - I can't see any benefit in expressing before you feed, BTW, not sure why that's been suggested : )
Good luck, and try the NCT line again if you need to.