Overstimulation is actually quite a common challenge with a number of conditions, but especially so with Autism (and sensory sensitivities and all that can occur with it) and it can be a tricky thing to manage. It varies person to person as to how they cope. A lot of times the best option would be to remove yourself from the stimulation. For me it's cause my brain goes through information (not to mention it can't filter out info like irrelevant sounds) a bit more slowly and it gets backlogged, so that allows to to back process and become ready to get new info. Other coping skills can include things like slowing breathing rate (like box breathing), or various methods of grounding. If it's helpful I can share more in a follow-up comment, and/or my DMs are open.

When I'm overstimulated I like to sit down in the shower and turn all the lights off. It helps me re-ground myself. I do this when I have migraines as well (obviously I take medication those times)