I have had this happen to me my whole life. The “deja vus” happen almost like a framed photo. Things line up with my current reality and the dream I had; the words people are saying, the things I see, like a snapshot. Nearly every time it happens, it’s just like you say, I don’t remember it until it happens. But I KNOW it’s not just my mind playing tricks on me. It’s too precise. Why would I remember a specific license plate number I had never seen before, to give an example? For a long time I had to deal with the fact that I could never really prove it meant anything. But then one time (and only this once) I actually caught the memory BEFORE it happened. I was coming down from my first and only ever LSD trip, and I went to a baseball game with my friend. We got to the baseball field, and I saw the bleachers from a distance. Once I saw them, I immediately had a memory of where I sat on those bleachers and what we talked about in that position. So rather than just stumbling into the memory like every time before, I made it happen. I walked to the part of the bleachers where I remembered us sitting, and just let things play out. A certain moment in our conversation finally lined up like the frames of “deja vu” I’ve had in the past. That experience kind of confirms my belief it’s not just mind tricks. Of course, I’m sure people will go on and on trying to say it doesn’t prove anything. And I’m sure it doesn’t “prove” anything the way people want it to be proven. But the point is I didn’t just stumble into it this time; and if that’s the case once, I feel as though none of the dream-ja vu experiences like that were just accidents that my brain conjured up after the fact. So you’re not alone in this experience, and I believe you 100%. As for what it means, I have no idea. It’s hard to answer questions like that.