Lactose intolerant baby

My son has always had issues with gas and tummy aches since being born and he is now almost 11 months old. We got allergy testing done to see if he was allergic to milk or soy as we have tried so many formulas and nothing makes him happy except alimentum, which is making us broke.. the test came back negative saying he isn’t allergic to anything but is it possible for him to still have an intolerance? His pediatrician told us to try gentlease and he’s been on it for 5 days but he is miserable with gas, spitting up and terrible sleep.. what formulas helped you guys if your baby was intolerant? Or what did you do?