Hello and thank you for responding. Your son may be experiencing too much anxiety as well as depression from the academic demands of school...even at his young age. Related to anxiety and depression is ODD: Oppositional Defiance Disorder. If he is having a persistent pattern of temper tantrums, angry and disruptive behavior toward authority figure, defiance and refusal to comply with adult requests and rules, disobedience, being easily annoyed, academic problems, and a difficulty maintaining friendships, then he may have ODD. It may be beneficial just to be on the safe side to have your son evaluated by his pediatrician. He made need counseling to build back up his self-esteem.
Hope this has provided you with some insight.