I hope its "just" a cough, the normal sort. If its worse tomorrow, ring around and explain the situation, if it is whooping cough he needs to be seen. I had whooping cough as an adult and its hard on your system, but it has a whooping sound to the cough once it gets going. Croup sounds like a seal barking almost. Hope your little man is okay. It can so worrying when the littles get sick.