Lactose Intolerance
I've been aware of my lactose intolerance for 10 years, before that was 5 years of the standard symptoms that you know all to well.
There are several good lactose intolerant web sites out there, although I haven't been there in a few years. It's easier for me to cope since I live in California and have a multitude of options. (Milk from Soy (5+ brands, oats, rice, almonds - my favorite, and combinations of grains) In the San Francisco area there are even bakeries that make vegan gourmet cakes, including chocolate, carrot, etc. that are heavenly. I get one every year for my birthday and noone believes it's vegan/non-dairy. I could go on about the brownies, chocolate, Amy's Macaronie and (fake) cheese but that would be teasing.
Seriously, do some research on the web about the Jewish Kosher traditions. They aren't allowed to eat meat and dairy at the same meal, nor use the same utencils/pots/plates to prepare these types of food. So if manufactures are up to par including getting inspected on a regular basis by the Rabi then they can use the kosher symbols on the packaging. some of the typical are a U or a K. Just kosher isn't enough for us. Look for kosher meat or kosher 'pareve' (no meat or dairy, meaning they can eat it at either meal')This has been a huge help in the ingredient reading quest.
In the US, if an ingredient is less than 2% of the product it doesn't have to be on the label. The advantage to companies using Lactose is its a cheap sweetner that the dairy industry use to dump, and a small amount goes a long way, therefore it doesn't always show up on the label.
Finally, There are great products that are dairy free, but in my travels I seem to only find them in California. That being said, I'd see if your local co-op / healthfood store can order some of these products. When I lived in Germany I shipped myself sweets, LUNA bars (like cliff bar but dairy free), packaged brownie and pudding mixes.