I have chronic depersonalization with bouts of derealization and when I enter into the world of derealization I have memory lapses and my external world is absolutely taken apart, as if I am in a TV show. I don't know what other symptoms you have but you could look up the Wikipedia article on "depersonalization/derealization" and see if it pertains to you...

Good luck & I agree that meds aren't the answer when you see some family physician for five minutes who gives you the little depression handout & a script for Zoloft...