derealization can be caused by smoking pot but can be caused by other things as well, anxiety being one of them.
http://en.wikipedia.org/wiki/Derealization#Causes
Speak to your family doctor and get a good check up and discuss these feelings with him.
Hi there, I don't know exactly what you have but it's common from what I've gathered after being on this site for awhile. I get that too. I feel like I'm not real or that I'm just living in a dream. I know it can be horrible but you can get help. If your parents don't know this already you should tell them because they can support you through tough times and can take you to the doctors. And I used to smoke pot to but I quit smoking it like a year and a half ago. And I've been told by a doctor that it's not the pot that makes you get these weird feelings. I'm telling you this because I would and still do torture myself into thinking that I brought this on to myself because of my smoking. I just don't want you to torture yourself into thinking that you brought this on to yourself. Dude, you are very much real and so am I. I bet you may even feel that all the people on this site aren't real but everyone here is also real and is here to help and support you.