This is something that has happened to me from time to time since I was in my twenties. Ive never heard anyone else describe anything like it so wondering if it is just me. If you look in a mirror for a few minutes do you ever get the feeling that you are separate from the image you're viewing? Almost as if you don't really recognise the person in the mirror as 'you'. Then if you continue to look, you begin to feel freaked out and a bit fearful?
Fully prepared for the fact that this might just be me 