Time, more correctly, is a place rather than a flow. If you can feel that in yourself, then you can also learn how to move around in it.
Also, and this is completely delightful, you can feel what I call "the wind from the future." It's an actual source of nourishment that people cut themselves off from and then grow old. It's so unfortunate!
But never make the mistake that the future is set in stone. It most certainly is not! It has its own rules. When you learn to feel it, it's rather like Alka-Seltzer, the most delightful effervescent hard to even explain thing.
The past, to paraphrase Faulkner, also hasn't gone anywhere. If warm chicken (or vegetable) soup were solid, deliciously jello-like, it would feel somewhat like that.
The deja-vu thing, no offense, though, can be a little more mundane. If you're very close to someone, you can sense the word(s) they're going to say before it comes out their mouth. The word, the thought, assembles itself in your brain just before your muscles engage to say it. Nevertheless, if you can do that trick, it also shows that you've dipped into that space where we are all not really so separate as people in their unhappiness are taught to believe is so.
Or... you may be feeling a bit of that wind, after all!