Derealization what is it?

after smoking pot dont think of me as a druggie this was only my second time experiencing simply fitting in i still felt somewhat in a high state i know that the thc cant stay in my system that long so i knew it must have been something else one of my friends told me to check into something called derealization i checked out what happens to you and its exactly what im having i simply want to know does anyone else think that it might be derealization