This happens to me all the time.

I'll redirect to a post I made under "sleep issues & dream interpretation", maybe this is what you're partially referencing?
http://forums.psychcentral.com/showthread.php?t=219312

But also, I tend to remember conversations that never happened. Or life events incorrectly. I think even memory can be shaded by delusion. And I read something about memory recall in Schizophrenics. It doesn't happen to everyone, from what I understand, & it's not due to a lack of episodic memory... Rather, it's as if we make **** up without realizing we're doing it at the time? And even during different circumstances, one memory might shift drastically.

http://www.ncbi.nlm.nih.gov/pubmed/17506924
http://en.wikipedia.org/wiki/Confabulation