Welcome to the PNF Light Side. Dreams are fascinating aspects of our lives. When they show you things or events, there are reasons. Hopefully your dream was good glimpse and not a warning. Usually are a roll-of-the-dice chance to what you get next.
deja vu, dream based, is actually quite common. lots of info on it that can be found, i think almost 2/3 of people have experienced that or similar. studies have shown that it can be brought forth by different things, certain drugs, travel etc... it seems to decrease with age, interesting info to be found... been a while since ive dug into that scene, but a quick google search should give you some things to read up on.