Tunnel vision

Certain environments seem to make me go into what I can only describe as Tunnel vision mode. 

It's really hard to explain. 

It happens sometimes in environments where I was initially okay but then something happens (not always sure what the pattern is that makes this tunnel vision thing happen yet) and it happens in environments where everything is far too colourful, noisy and crowded. Corridors that are narrow with lots of people in them also cause this to happen. 

The tunnel vision thing itself it feels like I've sort of shut down and I'm in tunnel vision mode to cope with the environment. But sometimes I find myself getting anxious while in this mode and then the shutdown turns into a meltdown. 

Usually, because I'm trying to communicate something, trying to communicate I'm uncomfortable but yet can't find how to explain. Partially because I don't always know exactly why I'm uncomfortable. Especially when there feels like there are a bombardment of things going on around me that I can't pinpoint to one thing and just say "It's too noisy" because it's everything and nothing all at once. That plus peoples reactions to things I'm uncomfortable with often make me feel pathetic. It happens to me quite a lot in a queue, and people will say to me, "It's only a queue We all have to do it!" I find sitting down in a queue for some reason helps?  It also happens in public toilets. Tunnel vision on. 

Even though I think the tunnel vision thing is my brain's automatic way of coping with the overload, it's usually not a comforting feeling. 

I think I spent the majority of my childhood and adolescence in tunnel vision mode. This made me often quite clumsy. Tripping over things, banging into things, trying to open doors the wrong way etc. 

I was at the seaside over the weekend. One of those really commercialised ones where there are colourful signs and booths and generally a lot of people around with their kids. Even though being in a wheelchair helps somewhat (I use it for mobility issues not autism itself) I still went into tunnel vision mode. There were bright yellows with white writing, black with yellow and white writing and other colours just everywhere mixed in with the noise of kids it felt like the world was closing in on me. 

It's just come to me, it feels like you're in a place you'll never get out of. This sounds like an anxiety though? 

Is this an autistic thing? Do any of you get this?