Firstly, you are doing so well Mel. Way to go! Try not to be discouraged by the weight loss.

I wouldn't be worried just yet but I would be trying to get more feeds into her (around 8-12 feeds in 24hrs so every 2-3hrs). Imogen was quite like this -- a very sleepy baby -- so I had to wake her for feeds. I would be waking her or not necessarily waking her but having her attach more often. I know you said she can struggle to feed when tired but sometimes they feed their best when still asleep so is it possible to maybe lay in bed with her and feed her while she dozes? It took about 2 weeks of waking DD to feed before she really got the hang of demand feeding (she was a small and early bub though so might not take this long).

Thinking of you.