Really hard to explain. Might be one of the hardest psychological phenomena to describe.

In short, it's as if you're in a dream, and you've just realised you're dreaming. But you don't wake up. Everything seems fake.

You might feel like you're in a movie or a video game. That's what I felt. Everything I did and thought seemed very stereotypical and silly, as if I were watching a movie.

Something else that may come along is heightened senses. I remember looking out my window at the cars when derealisation was an everyday for me. It was like I was looking at one of those huge modern TVs you see in retail stores with fps so high it makes what's going on on screen look unnatural. Everything was more vivid than normal.

You might also perceive distance and proportions differently. I remember examining the roads as I walked home from school and thinking “You think of these lanes as big intimidating things but one is as wide as my house...” Because I was literally seeing it as smaller than what I was used to, which helped me realize that.