Wait for the strep test (ours came back positives while their throats looked fine) to rule that completely out.
Also it sounds like things are just piling on top of each other. Change in the classroom means insecurity, means can't sleep well, means is tired and unable to control himself/emotions etc. Oh and he's little, so they can just be that way sometimes too!
Be patient, be consistent as possible and be loving (I know you are)! And yes he might has strep even though he shows no immediate signs, so wait to confirm! Hugs girl!
