Snowman symptoms and conditions

My 5 year old son was put on for very mild asthma before xmas. After he returned to school, the teacher noticed he was not listening, difficulty attending, talking nonstop ( normally quiet), and repeating the same questions. At home, we noticed complaints of tummy aches, after 2 weeks very loose stools, irritability, extreme difficulty attending to any task, disorientation, rolling around on the floor, tic disorder; he started flipping his head side to side as if he's checking for something, and poor sleep (3-4 times awakening) esp. w. vivid nightmares, eg. crying because his snowman was melting and dying and dry nasal passages w/ bleeding sometimes. I notified the asthma/allergy doc. that we were going to discontinue. It has been a week now and his stools have formed better, not complaining of tummy aches, but attention/concentration still an issue as are tic movements; also came down w/ sinus infection so perhaps being sick is attenuating these symptoms. I hope he can get back into his zone. We are worried.