And probiotics, binding foods, along with adequate water intake
Fruit and spinach- grapes help me when my stomach gets really messed up and throwing a little handful of chopped spinach in with scrambled eggs in the morning really sets me up to be on track
Blueberries too! They have a lot of fiber!
Ever dewormed yourself? Pregnancy makes your dormant round worms wake up and they go through your breast milk. Round worms can cause diarrhea. Not saying that's what it is, but something to consider. Pyrantel pamoate is over the counter in Canada just ask for it. If you have to get something prescribed ask for fenbendazole as it does more species.
Bananas can help with diarrhea.