I was diagnosed lactose intolerant as a very small child so I say welcome (unfortunately) to my world.
It is easier now that non-dairy, lactose free, soymilk, almond milk, etc products seem to be readily available. When I was a little, my options to pour on my cereal were water and orange juice.
The pills don't help me much at all.
I do occasionally cheat but I have a pain vs. enjoyment scale that I balance everything on. Stinky french cheese bought at a Sunday market in Paris to enjoy with a baguette and a bottle of wine while sitting under the Eiffle Tower? Absolutely worth it. Slice of American cheese on a white bread sandwich? Not worth it at all.
You get used to dairy being hidden places it should never be hidden, reading labels, asking questions.
It's rare that I can go to a restaurant without altering menu items. I'm used to that. What frustrates me the most, though, is when they don't understand that yes, even a little cheese can cause me an issue.
Yes, I'm lucky that it is an intolerance and not an allergy, but I want to look forward to eating, not dread pain afterwards.