Is this some sort of de ja vu?

Every once in a while I get a tiny glimpse of some memories that I cannot place. It is like remembering a dream. What seems peculiar is that I cannot find anything recognizable in these memories. Like they are things I did not experience. They last at longest 2 seconds usually. Like dreams, if I don’t concentrate on them very hard, they slip away.

I think it could simply be my brain remembering very intense strange dreams, that seem to involve experiences I’m inventing subconsciously.

Is there any information on foreign memories?

I don’t, and have never used narcotics. I drink very little alcohol. If that helps.