We just went through something similar with my son who just turned six. He has been so sick for almost a year. The past six months he was on six rounds of antibiotics, mostly for ear infections, but before that he had only had one ear infection in his life, so the doctor wanted to figure out the cause rather than immediately putting tubes in. His pediatritian tested for allergies rather than waiting to get into an allergist. I could write a super long post, but the short story is that we got him a new mattress, cleaned the air ducts and carpet (have wood floors in most of the house), change his clothes after he's been outside to keep the grass out (one of his main allergies), are trying to find a home for our cat, and had a great treatment done to the dogs that gets rid of much of the loose hair and dander. We do have him on Zyrtec daily now, and it has been an enormous help. He was very irritable when on antibiotics, but I see no change in behavior when he's on the Zyrtec, except that he's happier because he's sleeping better without coughing all night. I hope you find something that helps with your son. It's hard to see them miserable.