I have had the extended deja vu. It does feel like an extended dream. I also remember feeling to pay close attention to detail. Almost like "here it is again, pay attention". Have you ever been with a person having deja vu at the exact same time? I recall one instance when I was younger where my cousin & I both exclamed deja vu at the same moment.
I find it interesting that most of the people I am around will exclaim it and everyone pays attention. There is a sort of reverence in it from my experiences. Interesting.