Rage in my child

My son (6 years old) has such rage that he is unable to control himself.  I am so concerned about when he gets older and hormones kick in as he has violent outbursts now.  He was diagnosed in November but he is high functioning and his school is working towards an EHCP so he can go to a SEN school as he was excluded last week and keeps having these rages in school and throwing things and kicking and lashing out at furniture.  Sometimes there is no reason I can see for it but it's all consuming for him.  I feel an inner sadness as I want him to be happy.  does anyone have any advice on what I should do when he has these rages as he is vile to me with his words and actions and it's hard to deal with.  He looks me dead in the eyes and says he hates me and it can be quite scary.  Am I over reacting as he can be loving too.