Just to reiterate I am not angry with the school or working against them. If that was the case I wouldn't have gone to the pediatrician the day after the meeting to get a referral to the psychologist or immediately reduced my sons hours.
I'm sensing a gut feeling something is off with the school. My son was happy to attend up until a few weeks ago, he used to say he liked it, likes the "toys" likes the teachers etc. Then I went away for 4 days and my DH & MIL took care of him but during that time he was very very upset without me, recovering from a cold so that didn't help but barely ate whilst I was away, cried alot and I know for the 2 days he was at school during that time he hit a teacher.
Since then his behaviour has been worse at home and presumably worse in school, ive noticed him coming home with scratches on his face too. His speech is very good so I've asked him about what's happening in school, he will say he feels sad in school, he doesn't want to go, doesn't like the toys, and doesn't like one of the teachers (main one who cares for him - he's in 3 adjoining rooms, 3 teachers, 20 kids). I've noticed he's biting his nails (new thing) - when I'm talking to him about school he says his fingers are hurting (from biting them), I ask when did he start biting them, he says in school, I ask why, he says because of his teacher (main one). It's the main teacher who I think has taken the brunt of his aggression. This week I received an email to say that teacher was leaving, quite abruptly and she was being replaced so this may help. If I ask him why he hit someone in school his response is usually because "I want mummy, I don't like the toys at school, I want to stay at home".
My previous concerns raised to my pediatrician were about how angry he is, he has an explosive temper, always has, nothing works to control/manage it, it's often unpredictable and a pattern of behaviour that he's never grown out of. He keeps repeating. Often it's a reaction to "no, you can't, stop, or if I've asked him to do something he doesn't want to do - wash his hands or get dressed, go to the toilet". Sometimes it comes out of nowhere - he will pull my hair, try to bite my hair, throw things at me, swipe everything he can off the table, hitting, kicking" the only thing I can do stop it is hold his hands to physically stop him. Then the only thing that calms him is a cuddle. When he's calm I explain why it's not OK to do x,y,z and remove whatever has been thrown as a consequence. He will say he feels sad and angry.
Believe me I've tried every parenting method to tackle this - books about what to do when you feel like hitting, time outs, removing him from the situation (often effective), redirecting where possible, suggesting alternatives when he feels angry, ignoring bad behaviour (when safe to do so) and rewarding good I set boundaries - but nothing works - it often feels impulsive and more recently attention seeking.