Just remember that you have no control of what happens at school.
Thus you cannot hold yourself responsible.
School staff willingly guide the children and are responsible for what happens within school hours. All they can do is inform you and all you can then do is talk to your son.
I am having the very same problems with mine who is a July baby.
keep it in perspective (this from some one who went to see the teacher in floods of snotty sobbing tears 3 weeks ago)
I too tried football etc, but we had to give up as my boys attention and interest lasts for all of 30secs.
That is normal, healthy little boy behaviour i have to add.
For me, i am riding the storm until it ends, and it will end soon.
Communicate with the school staff, take their advice on how to tackle and guide your boy, they have seen this a hundred times before you got there dont forget.
Talk to him about his day, although mine just says that he cant remember what he has done!
Try to focus on positives no matter how samll with him.
its not the end of the world and it will be fine honestly.
Lastly, never ever feel embarrased of your son, be proud of the spark that he has, ok agression or rough play is not a plus, but think of the confidence that he has, think of the great things that he does.
He has spirit, like my boy, and i am reluctant to squash that spirit, i want to re direct it.