Hi Jen, I have a very similar situation to yours. Also been breastfeeding my very sensitive LO on an extremely tight diet. She improved on it but still was quite bad with 5 or 6 nwks and mucousy poops. After months of pressure from paeds, I gave up breastfeeding and switched her over to neocate. It was the hardest thing I had to do and 3 months down the line, I'm still grieving it. Wish that I, like you, hadn't given up. Especially that since then we are battling with constipation. She improved on neocate since she doens't have mucous in her poo, no cradle cap and improved skin but there is this new problem of constipation. She is on Movicol which seems to be helping but not always and we have to use a suppository too to get things going. Very hard to work out what she is reacting to and whether the constipation is a sign of allergy or just constipation. I was told she could just have a lazy gut that will sort itself out in time.
The following are defo constipating: apples, carrots and potatoes. In Hungary where I'm from, mothers are told to avoid these. Instead try peach, apricot, prune, green beans and peas should all be good. I tried prune juice but my LO had very sore tummy from it even though it was well diluted.
Is your LO very windy, too? Mine is.
Apart from this time, does she normally sleep through the night? Mine always wakes a couple of times and takes a bit of milk. It does seem that she is woken by being sore or uncomfortable but I can't work out what's causing the problem.
Her diet looks like this.
Fruits: either pear, peach or apricot
Veg: potatoes (I only use as a base), butternut squash, sweet potato (interesting that people are saying it's constipating, might try and avoid and see what happens), swede, broccoli (very windy, so I rarely give it)
grains: millet
Tried chicken once but going to hold off, she seemed to be unsettled after eating it.
Sorry for rambling on, not sure if this helps at all.