After reading more of your comments op, it sounds to me that the school have been trying to nudge you in the right direction, the extra support, picture timetables, warnings in advance of change, in my head, all point to a potentially big issues,
It is totally unacceptable behaviour to attack a teacher, my son has probably done a lot worse though and with the right communication it can be sorted in ways all parties are happy with,
You need to do your bit too though, I can understand as a mum you don't see the issues that other people might spot, but this is your oppertunity to open your eyes and start acting positivly for your dc,
Speak to school, get everything in writing, everything, copies of ieps, a report from the ht and senco with exactly what happened in it to end up in him being excluded, a signed letter giving a summery of dc's behaviour(on headed paper), copy of ep report (doesn't matter if its hand written, its a report), my ds now has a risk assesment plan because of being violent which states he will be excluded if he puts himself or somebody else at risk of harm or injury, does yours? Get a copy if yes, its quite possible if he has been violent and thrown things,
Next step, take all the evidence with you to see the gp, you will get referred because they would rather rule a problem out than miss one completely,
And then you need to go back to the school, communicate with them with an open mind, they spend a huge amount of time with your dc, they will have insight you might not, ask them what you can do to support your dc at school (I sat in afternoon lessons for 3 weeks whilst my lo was with a sitter) try everything they suggest, you can't be faulted by anyone if you are doing everything you can,
I don't really know what's happened I'm not normally this verbal on here, but I do speak through experience and know it can be a hard to think your child might not be "normal" but even if its something minor you need to help the school and your ds deal with it, its not fair on anyone for this behaviour to continue
Good luck