Kid recently diagnosed with ADHD

So my 6 yo son has been diagnosed a few months ago. To me, it was a relief to know that he has this condition, and everything started to make sense some how and I was able to set expectations and don't fell frustrated whenever he wasn't able to accomplish a task. So I've been more patient and able to understand him to encourage him to not stop trying. But I'm feeling low because I don't find the way to cope with school and parent from school. My kid has been labeled as a violent kid, this came to my knowledge last week (we are now close to summer vacation in my country). So this might explain a little bit the reason he hasn't been invited to any friend's house during the year. Maybe, not 100% sure. My kid isn't violent. I know he is reactive. That is what we have been working since he is very little. He never asked for any adult help whenever he is having troubles with some other kid. He doesn't cry if someone else hits him. He just resolves the situation by himself and that has always gotten him into trouble, because the other kid ended crying and he seems to be the guilty one. We are changing school now because the current one has a very disruptive class with most of the kids struggling to manage their feeling in an assertive way, so my son doesn't have many positive examples to follow. And he gets distracted by these kids and always like to get involved in any wild situation. We are working now on his self acknowledgement, because he thinks he is the worst kid at school. I hope we have the chance to bond with new families and kids that help him learn better and lovely ways to connect. Have you gone through something like this when being a kid at school? Something you think might have helped at that time? Something mums can help with? Maybe talk in advance to the other families and let them know my si condition?