Hi - My son was also very cranky after I ate dairy products. He also broke out in a mild rash on his face, head, neck and shoulders after I had dairy. I did not connect the two items (I thought he had a bad case of baby acne) until I read that a dairy allergy sometimes causes a rash only in those areas. When I eliminated dairy in my diet, both the crankiness and the rash cleared up. I do not believe it was lactose intolerance, but an allergy to dairy products, which is fairly common in infants. My son is now 19 months old and does not seem to have any problems eating dairy now. We tried letting him have dairy every now and then and once he passed the one year mark or so, he would get a slight rash and really no crankiness, now he has no problems.
Personally, I would avoid dairy for him for a while, and then try again in a few months and see how he reacts. He may grow out of the intolerance too. Good luck!