Honestly, what a useless mother I am !
PLEASE don't feel that way! it takes a looooong time to get used to reading EVERY label and to not have slipups. seriously, at this point just take it one meal at a time and pat yourself on the back for getting through another day dairy/soy free!
FWIW, my DS is 2, been dairy/soy/gluten free for almost a year now, and it took me 6 months before i was feeding him "perfectly." and, just yesterday, i told DH to give DS a fruit pouch (squeezable baby food) as a treat and instead gave him big sister's YOGURT pouch. and the pouch even says YOGURT on the front of it. so yup, DS had milk yesterday and yup, 4 hours later had horridly soft stool. my DH is a lawyer - he usually reads everything LOL. so...sh*t happens. as long as it is not an anaphylactic or systemic reaction, it WILL be ok and you and DS will move on.