an overload is when your brain just says "TILT!! !" and you just can't do anything until you get some downtime R&R. it is inclusive of being overwhelmed by obnoxious noise and confusion but goes way beyond. for more clarity, a good physical example is when a diabetic gets a low-sugar condition and goes into a foggy mental state just before diabetic shock, where he or she just cannot think straight or do much of anything until receipt of some glucose so the brain can function again. i am a hermit now basically to avoid situations where i would go into overload. when i am overloaded, i am like the aforementioned diabetic, in that i just cannot think or do anything but just lock up until the stress goes away. everything outside of myself just becomes a noisy obnoxious blur. this happens when too many people demand too much of me at the same time.
there are different types of overload, with different mixtures of stressors, and one that is unique to a relatively few people, is Stendahl's Syndrome, where exposure to great beauty [art, music, nature, magnanimity, etc.] causes some obscure emotional regulation thingie [possibly related to fight versus flight] in the brain to switch off, resulting in extreme emotional stress. there is very little written about Stendahl's Syndrome but that in no way diminishes its impact on those of us who have it.
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just my 2-cents' worth, adjusted for inflation