Déjà vu...

Well, that's a can of worms you've opened.

Science claims it's an anomaly of memory, which creates an impression that an experience is being recalled. Usually, the sense of recollection at the time is strong, but that the chance of event being in the past is uncertain or believed to be impossible.
There is little or no evidence to support this conclusion. Usually, these things happen without scientific observation. Some inconclusive research has been done with people suffering from temporal lobe epilepsy or under the influence of certain drugs or medications.

A popular explanation is that the memory is acquired by perceiving the future before it happens, yet there is also little or no hard evidence to support this conclusion.

As for the anomalous condition in which a future event can be known, then later recalled as it is happening, there have been reports by people who record their dreams in detail, in writing, that occasionally their dreams manifest in detail days later, which is supported by their earlier recording. Science rejects this possibility because time, as currently understood by science, is linear. Such events are usually attributed as anecdotal or as faulty memory or perception.

One thing to consider is that déjà vu usually occurs while one is in a distracted state, or as you describe it "feel(ing) something was 'off'." Since one is not concentrating on the present moment when this occurs, it brings up questions regarding the nature of our perception of time.

Many theories or questions, no solid answers.

Be aware that déjà vu has been reported by over two-thirds of the population, and most frequently occurs in healthy individuals.

Impossible is illogical.
Lack of evidence is not proof.
 +  = 

Very interesting, thank you.

Play with monkeys, put bananas in hidden places