I also had some kind of depersonalisation during high school. When i looked into the mirror i didn’t recognize the guy that looked back at me anymore. What my brain said i was, wasn’t to be seen in the mirror. My brain probably expected to see a girl, but she wasn’t there.
Deep down i knew the person the mirror showed me was supposed to be me, but it just felt so disconnected and far away. The image the mirror showed and what i felt like didn’t add up. Sometimes i even felt like some kind of emotionless robot with no control over his body.