I think i know what you are talking about. I experienced this right after a chain of nasty panic attacks. The feeling where your not there and like your watching yourself in a camera... like your "out of sync" with reality??? I read up on this after searching for months...Something is not getting to something fast enough in the brain lol so detailed right.. WELL ANYWAYS
HOW I BEAT IT!
First off, you have to quit checking in on yourself to see if "its happening".
Its the checking in that pretty much causes the derealization
Tell yourself its going to be ok
say " i am ok, everything is going to be fine"(HELPED ALOT)
talk to yourself....
Have a list of things to do for the day dont sit around... keep your mind focused on other things..
also playing a song that is of great memory to you will help greatly!