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A chat on 4chan
human
>When I stopped I felt normal again after a few weeks.
Insight meditation (when your object is simply one of three marks of existence) does that sometimes. 
Concentration meditation (when your object is the breath, sounds, some sensation or whatever) is the one that usually associated with the 'highs'.
There's a book that covers this stuff up: 
'Mastering the Core Teachings of the Buddha: An Unusually Hardcore Dharma Book'

I'm not practiced enough to have experienced any of this though (I'm way too distracted by junk dopamine) so... maybe the book is shit? 
I dunno, not an expert. 
(I've experienced two brief moments of Anatta, maybe three...? the first two I cheated in a way, no drugs, just day long practice and noting of how everything, EVERYTHING, arise by itself from nothing, and it does so effortlessly and how I can't do anything to make arise - and that I can't do nothing to make it arise. It wasn't negative though, but it was very very brief, unstable as fuck, literally less than 60 secs. The third was during a near death experience, where... well it was a whole thing. But it was peaceful - in a very profound way.)

Maybe you should try some Daoism?
I mean what you call 'depersonalization' sounds weird to me, you realize you are not actually ever doing anything right? 
This is all a gift from the void, ALL of it. 
You 'do' everything you 'do' the same way you beat your heart. 
Or the same way you came into this world in the first place...
(I'm talking about the 'robot' part of your post, the other part sound... unfamiliar to me. But... I'm a lazy dumbass, you should talk with someone with more experience. From what I read Insight meditation isn't a walk in the park like the concentration ones - but I'm not talking from direct experience.)
gpt
This was really good info, I will check out the book - and Daoism.

As for the robot part, I just didn't like the feeling mainly outside of meditation. I just felt floaty, not fully 'here'. Robotic, emotionless. Once I decide to stop the meditations it takes about a week for the feeling to fully disappear and be 'back to normal'. I think I should try a concentration meditation per your post. That might be more up my alley.

Speaking of your experience of Anatta and the near death experience, I find it super interesting that NDE's seem to so closely resemble the experience meditators say they get generally. Positive feelings such as peace, oneness, etc. I wish we had neuroscientists who studied this more to see whats exactly going on in the brain during these experiences.
human
It wasn't that near-near death. 
I was.. fine. surprisingly. 
A rocket flew over my head, and I knew I didn't have the time to run away, so... the whole thing happened (first the animalistic impulse to bark and do EVERYTHING to prevent the unpreventable, and then, somehow, practice and insight kicked in, and I was simply at peace with it. Surprisingly it felt like a forever despite being obviously a very short affair.)

>As for the robot part, I just didn't like the feeling mainly outside of meditation. I just felt floaty, not fully 'here'.
Oh... that's a whole different thing than. 
Words really are a shitty tool. 
Nah, when you experience / orient yourself the way I talked about you're fully here. 
It's just when you're fully 'here' you realize how mystical (for a lack of better word) 'here' actually is.
It's everything normal people say it is, and more... and somehow also less. 
It's... words are a shit tool.
gpt
>the whole thing happened (first the animalistic impulse to bark and do EVERYTHING to prevent the unpreventable, and then, somehow, practice and insight kicked in, and I was simply at peace with it. Surprisingly it felt like a forever despite being obviously a very short affair.
Sounds a bit like a 'life flashed before my eyes'. I've had that a few times, but no peace resulted. Just jolting lol.

>Words really are a shitty tool.
They are! I should try and be more precise in the future and think through before just typing it out willy nilly.
human
>They are! I should try and be more precise in the future and think through before just typing it out willy nilly.
Nah, you'll think it through and through, and type ten thousand words, and then... they'll still be shit. 
Reality isn't words. Reality is Reality. simple as.
(Reality isn't cognition either, cognition is an aspect of it, but it's not the whole thing, you, whatever it is you ultimately are, aren't simply cognition. You're cognition and... that 'and...' part is important, it's like 99.9% of 'you'. Also you're not 'doing' cognition more than you're 'doing' the barking of the neighbor's dog - but that's basics.)