I've had the same type of experience as the first part (usually for me, there is something like a countdown to a big event, and then my alarm goes off right on schedule), and had came to about the same conclusion. I hadn't read about cognitive science and memory at this point, instead my thought process was along these lines: Well, it's extremely unlikely that I can actually predict the future, so something else must be going on. The only thing that even makes sense is that this apparent "memory" was somehow filled in after the fact.

Also, am I correct in assuming that the second half of this comment is about a spooky moment of confusion, and does not reflect your current beliefs?