Milk intolerant

What the heck is that? Have you heard of someone who’ll have runny poo poo after drinking milk? That’s milk intolerant. Unfortunately, Carina is one of them. After being sick from stomach flu for a week, her poo poo stays runny till now. The pediatrician said she’s having secondary milk intorlerant. Primary milk intolerant is natural born but secondary is developed from the stomach flu. The doctor said Carina is intolerant with the lactose in my milk. If I keep nursing her, I have to take a pill called lactaid which is a natural enzymes to break down lactose. The other option is switch to soy base formula. I’m planning to wean her at 9 months. I’m still thinking if I should do that now.