I don't want to dismiss your worries, sorry if it came across like that. If there's other day to day things which you're concerned about alongside the party issues, my advice would be to take a breather and find a time when you can sit down and write some points down. Think about what they struggle with, triggers etc but also what they enjoy, are good at, where they're most comfortable etc because it's all part of the picture.
Maybe even do a diary for 2 weeks - sleep, food, activities, behaviour. If you feel like things are jumping out at you, take them to your GP and the school and just see what they say for now and go from there.
Online there's some good resources, geared towards ND, but also good solid tactics for all kids really, especially maybe ones who are more sensitive. The contented child is a good page I've found.
I just get a bit annoyed when a poster can ask about something (anything) and the first 3 replies are "they probably have Sen" despite very little information. It's always geared towards "negative" behaviours too - lashing out = Sen, doesn't listen = ND, posts about awards etc for doing well = oh but what about kids who aren't doing well, they probably have Sen... It's like they find it impossible to believe that kids who are autistic or have ADHD or other differences are actually capable of anything and it really annoys me.
Sorry to derail!