As a child I used to get “trapped” in the corner of the room - I’d be lying in bed and my consciousness would get locked in to the corner where the walls meet the ceiling. Felt like I was pushed hard into the corner

Never heard of anyone else having this until it was mentioned on hacker news a while ago and someone linked to Alice in Wonderland Syndrome which matches my experience perfectly - maybe your geometric nightmares are like this?

https://en.wikipedia.org/wiki/Alice_in_Wonderland_syndrome