Food Allergies Treatment

Ok lets start off with hes not crying or having any symptoms other than the below stated…
With MILK, he drinks it, and wakes up every 4 hours wanting more bottle and crying. And takes a 30 minute nap all day
With Soy he drinks it and sleeps all night, and takes a 2 hour nap.
Im confused as to it being a allergy cuz he has no other symptoms than sleeping less. and waking crying.