Lactose intolerant

Has anyone dealt with a lactose intolerant baby before? This is my second and his test results should be back Monday but if it’s not that i can’t understand what’s wrong. Somtimes he seems so uncomfortable during feeding, very fidgety and crying. His quite sicky, also when he poos (eventually) there’s SO MUCH as if it stores up then his in pain and he will Litrelly fill four nappies. We’ve tried three different milks too. Doctor said it’s normal for newborns not to poo every day but the frequency doesn’t concern me it’s the amount when he does go and how uncomfortable he is on the days he doesn’t 😩