PL, I'm sorry you're having such a rough time. Can I suggest calling the ABA Helpline 1800 MUM2MUM for someone to talk to? It doesn't matter if you've definitely decided on weaning, they will still support you. It might be nice to have a chat to someone to debrief.

Guys (I'm not saying that this is the case with you PL) lack of poo actually can be a sign of baby not receiving enough milk in the early weeks. You would expect a newborn to poo at least once a day. As time goes on, sure, lots of BF babies can go many days without pooing, but it is not to be expected for a newborn. Of course, it's helpful to look at the big picture, and check out wee output, weight gains, skin tone, baby's behaviour, and growth in head circ. and length. But poo is often a pretty good indicator of what's going on.