I didn't think DS2 had much of an understanding but he came home from nursery today (his last day) saying "name not x" eventually I found out they had got them to put their name cards in the bin, he was all over the place all evening & has been a bit like this especially with bedtime for a couple of weeks, he refused to bring a picture home that had been on the nursery wall.... just too many little changes for him.
I'm sure your ds's sn school are more sensitive than this though.
It could still be end-of-term-itis. Your son might not know it's happening but a lot of the others will, and there tends to be an excited vibe running through school at this time of year. You'll probably just have to ride this one out and see how he is when he settles next week, once school's over.
Mine's been mental the past couple of weeks. Partly because the school is crap of course, but also because they've been stripping down the classrooms in readiness for September, there have been 'special events' taking place over school - even those he's not been directly involved in have affected his class because they can hear things going on elsewhere and it does have an impact.
I think it's a case of "oh I've suddenly discovered play" He kept sneaking down to find his new toy thing again (kind of a building set thingy can't remember what they're called). ONly just gone to sleep. Switched sleeping patterns (hate it when he does that!)