M.A.
This sounds exactly like my son! He became hypersensitive too, hysterically crying at every little thing. I even took him to a child psychologist, but by the time we could get the appointment I realized that he had started a new nasal spray and quit giving it to him. It took a few days but he was back to normal, the psychologist even told me he was a perfectly normal child-whew! He has not had a problem with allergies yet since this episode but I just plan to suffer through it with no medication. The allergist and pediatrician both said to consider it an allergy to nasal spray and to not give it to him again.