Is it possible to suddenly become lactose intolerant in your early 20s, after never having shown any such symptoms before in your life? It seems that lately, any time I drink any significant amount of milk, or eat cheese (I like a lot of cheese on top of spaghetti or any other pasta), I have a bit of....let's just say digestive distress. It's nothing really that disastrous, and can usually wait at least an hour or two before I need to use the restroom, but it's still noticeable. What are the normal symptoms of full-blown lactose intolerance?