Future Nihilist, I know exactly what you are talking about.
Odd that there is so little activity on the Depersonalisation Disorder Forum, considering that this is the 3rd most common mental disorder after anxiety and depression. However it almost never happens alone and is usually a result of an another disorder, and I noticed that people tend to post on forums about those other disorders that involve depersonalization as an element (like the schizoid personality disorder forum, both here and schizoid.net). It seems that any disorder that involves very low emotionality and/or high anxiety will have an element of depersonalization somewhere in the mix.
Some threads where I personally talked about my experience with depersonalization:
About depersonalization:
http://schizoids.net/forum/showthread.p ... nalization
About being unable to generate any thoughts in one's head (also part of depresonalization):
http://schizoids.net/forum/showthread.php?t=1051