DS has started screaming and clinging on to me so tight when we meet other children. He has never done this before. We had a bit of an unpleasant encounter a week or so ago with a neighbours 3 yr old son who was prodding DS and annoying him and since then it's been awful. He won't go into the playpark if other children are there and clings to me if they come near. What should I do? He goes to a creche with other children (seemed ok there today in a familiar environment) and we go to the library for bookbug sessions as well as softplay and swimming so he is exposed to other small children.