This is the start of a concentrated effort through the whole growth cycle that you bring out in the child. Name calling and teasing are common ground at this age. Don't allow or accept name calling to persist in school. Have your child's teacher talk about and discuss differences of all children. When your child is absent, the teacher should talk to the children about your child.
Physical competition puts added stress on the child.
Child may physically be doing twice what you think he or she can handle. Your child must participate in all physical competition sports that they can. They may not be the winner, but they will not lose either. By trying, they build experiences and the self-confidence of belonging. This will point out to your child that they do belong.