I recently discovered I was Lactose intolerant.  How?  Well, I'd been having some vague digestive difficulties for some time, but didn't know the cause.  Then I went out to dinner at an Italian restaurant and had a delicious pasta dish with olive oil, olives, and BIG CHUNKS OF FETA CHEESE!  Yummy.

About an hour later things weren't so fun.  Major stomach cramps, volumes of gas, and frequent "get the h#!! outta my way" trips to the toilet.

I don't even know if there is a test for Lactose intolerance.  The chunks of feta did it for me......

Hi,

Yes, there is a special test for lactose intolerance that I had.  For about three months or more I was having stomach pains that were so bad that I was doubled up with the pain.  I was also spending long periods of time in the toilet.  Up to 30 mins at a time.  I got fed up with this so went to my docs.  He examined my belly thoroughly and did some blood work.  To be clear about the diagnosis, he gave me some lactose whilst there.  I went on a good day, but half an hour after the lactose I had the excrutiating bellyache and was then stuck on the toilet in my docs office for 40 mins.  

He was happy with his diagnosis then.  I have now cut out all dairy, take Acidophilis caps and take some digestive enzymes.  I now have no bellyaches and have normal bowel movements.  If I want dairy I take Lactaid beforehand and it seems to work fine.

Well, I have lactose intolerance that I got at about 20, I'm 24 now. My mom has irritable bowel syndrome. I KNOW that pain of feeling like you are going to die you can have both of them, depending on how bad it is in your own situation. Although the diarrhea is pretty bad. (I feel like I've taken a really harsh laxative).
I know my mom's IBS is worse when she's under stress, or eats real heavy foods (i.e. cheesecake, chinese, italian, mexican, and certainly if you eat too much at one time).
But you can try eliminating milk stuffs (read labels, a lot of things have lactose in them that aren't milk products, such as burrito seasoning...). Then maybe add some back in and see if you get that pain again within the next two days. When I first started sometimes it'd be as soon as I started eating something, sometimes not for two days... But just try that, you may be able to tolerate some, like I can tolerate a slice of say american cheese, but absolutely no more than that without taking lactaid. If it is lactose intolerance, which I hope it is, because their is lactaid and other alternatives to food.
If it's IBS, well that comes when it wants too and you have no control over it at all.
It could be something else altogether, but seeing if it's related to lactose is pretty easy to do and if it's not then I'd see the dr and get him to try and rule out anything else.