Taken from wikipedia:
Originally Posted by gonzoflick
With lactose intolerance, the result of consuming lactose or a lactose-containing food is excess gas production and often diarrhea
The normal mammalian condition is for the young to lose the ability to digest effectively milk sugar (lactose) at the end of the weaning period (a species-specific length of time usually equal to roughly 3% of lifespan). In humans, lactase (the enzyme that breaks down lactose) production usually drops about 90% during the first four years of life, though the exact drop and age varies widely. However, certain human populations have undergone a mutation on chromosome 2 which results in a bypass of the normal shutdown in lactase production, allowing members of these groups to continue consumption of fresh milk and fresh milk products throughout their lives.
most modern western Eurasians and people of western Eurasian ancestry show the effects of this mutation (that is, they are able to safely consume milk products all their lives) while most modern eastern Eurasians, sub-Saharan Africans and native peoples of the Americas and Pacific Islands do not (making them lactose intolerant as adults)
It is my understanding that you are either lactose intolerant or you are not.
Without lactase, the lactose in milk remains uncleaved and unabsorbed. Lactose cannot pass easily through the intestinal wall into the bloodstream, so it remains in the intestines. Soon, gut bacteria adapt to the relative abundance of lactose (relative to other sugars like glucose) and switch over to metabolizing lactose. Along the way they produce copious amounts of gas by fermentation.
The gas causes a range of unpleasant abdominal symptoms, including stomach cramps, bloating, flatulence and diarrhoea. Like other unabsorbed sugars, e.g. mannitol, the lactose raises the osmotic pressure of the colon contents, preventing the colon from resorbing water and hence causing a laxative effect to add to the excessive gas production.
Although there may be some threshold at which you are consuming more lactose than your body can break down. but i really have no idea.
If you're net getting excessive gas/diarrhea i'd say you're fine based off this information.