Have I had a similar experience? That is a significant part of why I got evaluated in the first place.
I never have explosive meltdowns, but I experience what you are describing word for word. I have since I was a child. I have very vivid memories of trying to hide in public places as a child to "dissociate". I have not had any singular traumatizing moment in my life, and the most traumatizing thing I deal with is the 23 years of masking every day and trying to act as normal as I possibly can when the "dissociation" sets in.
I think what you and I are experiencing could be some kind of meltdown. Some autistic people "implode" rather than "explode" with their meltdowns. Some of us may be able to keep our wits just enough to externalize our meltdowns and instead experience them in silence. I'm not sure if I was left in that state long enough that I wouldn't begin to externalize the meltdowns, and when I think that's about to happen, I leave a situation no matter how inappropriate or awkward it may be. I figure while I'm not fully saving face by suddenly vanishing events with no explanation, I'm saving more than if I started violently crying for no reason because I'm overwhelmed by how many people are in a restaurant.
Also, I've heard of some autistic people with this experience call it a "shutdown", while I've heard others who experience the more "explosive" meltdowns say that a "shutdown" is a response to a meltdown, where after they have an "explosive" meltdown, they may spend a day or more in a dark room with the decreased ability to tolerate stimuli and sometimes diminished verbal capability.
Terminology aside, you are not alone in this.
EDIT: Since I really started to burn out last year and stopped forcing myself into so many uncomfortable social situations, this happens much less frequently than it used to. It still creeps up on me when I feel obligated to go a crowded dinner or party, and I often experience the "rumblings" of it in grocery stores (it isn't happening yet, but I know the clock is ticking until it does), but it's not a multiple-times-a-month deal any more.
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Take it easy, dude, but take it!