I have experienced that after going through a trauma in 2004/2005. It hit me the spring after the trauma. Really strange spacey feeling. I still experience it but much less after all these years but only when stress levels get high. Something i don't experience that much after leaving where I was living & basically starting a new life.

DP/DR is when you are like watching yourself like watching a movie. Dissociation is when you are totally gone with no realization & sometimes loose time. Like when you are driving & wonder how you got from one off ramp to another....mild dissociation. If you watch yourself get there & are aware....that is DP/DR. The explanation I was given by my psychologists. Either is a strange feeling