Depersonalization is recognized by many psychiatrists/psychologists as the feeling that one is detached from oneself, that you are not real somehow. Perception and reality feels different, as though something might not be quite right.

Not to go off on a tangent about "other psychotropic drugs", but I had this feeling after taking a very large dose of LSA (not LSD). If you know about Owsley, he sold LSA-containing seeds which he said would get you , "not high but weird". This reminds me of dissociative drugs. I felt like everything was dreamlike. The best thing I can recommend is that if you experience depersonalization to an uncomfortable degree, stop smoking. Cannabis sometimes is linked to the manifestation of schizophrenia and other psychotic disorders --but usually only if a person is predisposed before smoking... I think we can attribute this to the hallucinogenic properties of cannabis.

(sorry mods if that violates anything, i'm not trying to advocate other drug use).