Lactose????

I got blood drawn a couple weeks ago to see if I have any food allergies/intolerances. They just told me that everything came back negative which is good... BUT! Apparently I’m not lactose... which is weird because everything I drink milk I have to rush to the restroom within minutes. It’s not just milk. Anything with dairy in it. My grandpa and my uncles (his sons) also are lactose, so I thought I had it too. Does anyone know of why i could be experiencing this if I’m not lactose?

Btw, I’m gonna ask my doctor about this when I go in to see him.