First of all massive and YOU ARE NOT A FAILURE, your a mum who cares about her baby who's tired and emotionally drained.
Babe we all go through it and while i don't have PND i can only imagine what a screaming baby and restless nights can do to you.
There are LOTS of men & women on here who have babies that don't like sleep, am hoping someone can come on here and give you some wonderful advice.

Does the MCHN have any advice on why she wakes often, is she a happy bub and just doesn't like sleep or is she constantly unsettled etc?

I hope you get some advice hun.. deep breaths, a failure wouldn't be so worried about her bub.