Also you need to ask yourself if you learned anything through your experience. Drugs like mushrooms, LSD, Extasy and the like aren't just fun to take and trip out on, they are also powerfull tools for expanding your conciousness. Even if you were in some kind of intense introspective nightmare for several hours it would still be a good trip if you came away from it with a better understanding of your reality or who you are.
Drugs can be both a friend who entertains and an instructor who teaches.