Being overstimulated is such a weird thing to explain to people. Like "hey sorry, I'm not mad at you and this is nobody's fault and I'm not blaming anyone for it happening, I am aware this is a part of regular everyday life but I am mentally crumbling because There Have Been Things Happening nonstop for 5 hours straight back to back with no breaks, and I really need to sit down in complete silence for like 15-25 minutes, after which I will be completely fine and can proceed as normal. But if I'm not allowed to have that, I will resort to violence."
Fun fact: people who care about you find it charming if you just...say this. You don’t need to explain anything, just say that you need to go sit by yourself in silence for a bit like you’re telling them you need to go to the bathroom.
...Actually, if you say anything casually with an air of “this is not a weird thing for me to say/do/ask for”, even relative strangers will roll with it because they don’t want to be the one who Makes It Weird. I once asked someone to take over note-taking duties for me because “I need to go run up and down the hall real quick”. Nobody even asked follow-up questions when I got back.