Milk at one

Have any of your children taken whole milk? I want to know if any of you found out your children was lactose intolerant and how you found out. My baby will be one in a week and I've been introducing whole milk for two whole weeks now, but I've noticed he gets really gassy and burps right after having the whole milk. He doesnt get fussy or anything and hasn't gotten a rash or the runs but he's hasn't been wanting to take milk before bed only solids and he wakes up constantly when he wouldn't before. Any of you experienced this??