Sounds almost like what I am going through. I get deja vu episodes for a couple days each month, and its usually accompanied by a headache. Its wierd though because sometimes at night when it happens my brain throws in some sort of misc character from tv and that character pretty much tells me that its going to happen a bunch the next day or something, I am still trying to figure that part out.
The brain is a very complex thing, I cannot even begin to understand it.
i forgot to mention that i am often dizzy (not that my environment spins alot, but my vision gets swirled slightly and keeps on swirling back and forth if i stare at something for more than 2-3 seconds with firm concentration).
Well, other than some serious problem, I used to get that when I didn't get enough solid sleep.