My son is 1 yr and 8 months old. Before 4 days he had 102 degree fever. I gave syrup  for 3 days and fever had gone.he is normal till yesterday. From today morning he s having cough and he looks very tired.fall asleep often and not taking food. What will be the reason? He s very active when he had fever. But now no fever but he looks very tired sleepy and not having food. Pls advice