I have no idea where to write this, doesn't seem exactly lesswrongy, but this is the only place where I expect to maybe get replies that might resonate with how I think. So,
Yesterday I had a stressful negative experience [that I won't go into], I had pressure in my chest, breathing heavily, I turned to my friend and said "wait, I'm not ok" and sat down on the steps, noticing that this is an unusually negative reaction, and decided to focus on noticing my sensory inputs, and a few moments later, to notice my thoughts too, as I sometimes [once a week?] do since reading Multiagent Models of Mind.
Sitting there, I notice that I see only a small "area" while the things around it are foggy (to the point that somewhat made me worry that I don't see well). I want to experience touch, so I rub my fingers against the palm of my hand and feel them. I pick up a small stone and notice it in my fingers. I notice my feet on the ground, in my shoes, somehow "far" from me, but looking at them, I see them somehow surprisingly close, as if a small optical illusion, which makes me think I'm not ok.
I notice my thoughts. I notice thoughts come up, and I am passive about them. The blog posts [that I linked to above] have "taught" me that I don't control my thoughts anyway. A thought of worry comes up and I notice it passively. A thought that I should stand up appears and I notice it. A reply to that thought such as "it's too soon to get up" appears after it. I trust that all of these thoughts and counter thoughts, including plans, will arise anyway, and there is no need for me to do anything about them. [This is pretty unusual, I'm usually active about planning things]
At some point I wonder if I'm having an enlightenment, which I find to be a funny thought, but I just notice it and at some point another thought comes up.
At some point I notice that it is not that "I am choosing to meditate" either. This "do meditation now" is itself another thought or habit or something, just like the others, and I wrongly assumed it was "me choosing to do that".
The next thought was that there is a "me"  that is noticing that "choosing to meditate" is not me.
So: "me"  --> noticing that it is not me that is "choosing to meditate" --> the meditator is noticing that thoughts like "should I stand up" are just arising and are not coming from "me" (the meditator's "me").
And I notice that this original "me"  still thinks it is choosing things, like to notice that the meditator is separate, and I intellectually understand that this is wrong (I understand intellectually that there is no choice there), but I don't actually experience it as wrong, and I don't dig into it.
About 15 minutes after sitting down, I get up and we start to walk along the street.
I feel somewhat detached from myself / from my body [I don't have good words for this]. I have to explicitly try noticing some sensation in order to.. notice it. For example, I direct my attention at my feet and notice them, feel the bottom of my feet strongly on each shoe, especially when the shoe is on the ground as I am walking. I can look somewhere and totally see it. But this is different from the normal way I sense the world, where I seem to have access to all of my senses all at once even without paying special attention to them. Usually I'd at least have an illusion like I can see everything in front of me, even though if you'd ask me, I'd intellectually know that some of my field of vision is just my brain filling in the gaps. It's like now, while walking, my brain isn't filling in the gaps as much.
I think that describing this situation to my friend would be a very very good idea. It seems hard to start, like talking requires an explicit choice or effort or something, rather than having my thoughts just pour out of my mouth, hardly noticing how it happens. I start with "I want to describe what's happening to me now, but I want you to mainly listen and not react in some really strong way".
5 minutes later, my friend suggests we sit down, and we do. I told them that I'm approaching this situation by mainly noticing my thoughts and senses passively.
A few minutes later, I feel somewhat tired, but also like I can force myself to wake up and/or focus, as if I'm starting to fall asleep, or as if I'm dreaming [I sometimes have lucid dreams and I know what mental motion I could do to wake myself up].
I ask my friend if they have tips on how to approach this situation. They ask if I want them to give a name for this. I say "an anxiety attack?". They ask if I want them to give ANOTHER name for it. I say no, but that I'd be happy for tips. They say "try not to fight it" (which is a common reference of ours), so I don't try to wake myself up anymore.
They ask "do you want to go to [some place]"? I answer "no, I can't sleep there". Them: "Is sleeping what you're doing now?". Me: "No", thinking "lol, what do I look like from the outside?". "But if I'll want to go to sleep, I want to be home", I'm very tired.
After walking a bit more, I decide to treat this as if I'm simply tired. I can also function reasonably while tired, so I can do whatever we need to now.
10 minutes later, we find a piano, and I play it.
20 minutes later, on the way home, I think “well, it’s not like I can decide what to think about anyway, so I better just keep observing [...] here, let’s test it, we just walked by a red car, let’s try thinking about that! red-car-red-car-red-car-red-car-...” and after about 10 seconds of that, I conclude “ok, maybe I CAN decide what to think about”
Since then, a day has passed.
I don't agree with my conclusion, that I was less aware of my senses, or something like that. Writing this right now, I notice there is only a small part of my field of vision where I actually "see" beyond the foggy part. I am not aware of what my body feels until I turn to it. I think the difference was that yesterday, I was aware of the missing parts of my senses, such as (the easiest example) the missing parts of my field of vision, and I was not under the "illusion" that my field of vision is complete. It is not that I see more now, it is that I'm less aware of what isn't there.
A part of me says that I should have some request here. There is no concrete reply to that thought. The part that suggested to write this post thinks that random good things might happen by writing it, especially if I tag Kaj and Eliot.
I don't really have meditation experience:
I went to a meditation group years ago, but it was mainly managing to stay reasonably calm and not having my head crowded with thoughts (thanks to an instructor who managed to give engaging enough instructions to occupy my brain on the meditation). I tried one of the meditation apps, but my head is way too crowded with thoughts, I couldn't deal with meditating for a few minutes, as it suggested. I'd also fall asleep sometimes.
Your detailed recall of the stages of thought, feelings and actions you observed in yourself is clearly recounted here. It seems that you were able to soothe yourself through focusing on being in the moment. The ability to detach from /notice what's going on around you and to choose 'red car, red car...' reminds me of my own attempts to focus on a basic meditation 'rising' and 'falling' of breaths, which is so challenging! It sounds like even recognising changes, for example to your visual acuity, you're still able to exist in the present moment - that relates, I think, to a meditative state, which engenders calm. Thanks for sharing your insights.