Hi Peta,
Exactly the same thing happened to me with DD but my MCHN told me to put her on formula as she was very concerned. I felt like such a terrible mother and felt like I had been starving my baby. I received such wonderful advice and support here which helped us greatly. DD was feeding every 3hrs so I started feeding 2hrs, both sides and dream feeding during the night. It only took a couple of days before she adapted and would wake herself after 2hrs and when I took her back after a wk for another weigh she had gained and my MCHN wanted to know which formula I was using to which I replied none. She was surprised.
I really hope it all works out for you both. Good luck.

Regards,
Dianne