yeah, i developed it when i was around 20. most people develop it around 18-20, but as it gets worse with age, a lot of people don't notice until they're in their 40s/50s etc.

i love milk, so i just switched to a lactose free type. it's brilliant - i can still have all the milky, milky coffee that i like .

the only way to get a proper 'diagnosis' is to take a sample from your stomach(? or other digestive bit) lining via a gastroscopy/colonoscopy. this happened for me, but it was part of a larger workup and finding out i was lactose intolerant was just a funny side-finding.

my doc did say that if i was already drinking a lot of (normal) milk, to maybe try to keep drinking at least one cup a day. so when i go out i still buy a normal cappucino, for example. apparently if you cut out all the dairy in your diet, then your body stops produce what little lactase it already does, and then your intolerance gets worse. i can still eat cheese, about 1 cup of milk, ice cream etc. but a huge milkshake would get me feeling pretty poorly.