I digress. Depersonalization/Derealization happens. It will fade with time. Usually within a few days...anything longer than a month is just a user perpetuating it by focusing on it. Don't focus on it and move on. You will move past it. I stand by my prior statement though. Actual advice. If Cannabis has triggered this and is temporary, anything else is decidedly unwise.
You were opened up to an idea that has been considered for a very long time. Don't shun away from things, harness the reality you possess. Face things forward. If you're in the matrix, break out. Fuck being the victim. I'm with you, a lot of smokers have felt this way too. But what's the options? Lay down - or keep it moving.