deja vu

I was thinking earlier, and just randomly i started thinking about deja vu and remembering all of the random times i've gotten it. Deja vu seems odd to me, and i dont quite understand it. I think it's just when you come across something that triggers a memory that you've long forgotten. I used to get Deja vu a ton, like for instance, i would start doing something, and then out of the blue i would get a flash back of when i did the very same thing years ago when i was little! Or i'll visit this place, but then i'll get this funny feeling, and i'll think, "wait, i think i've been here before..." But the truth is, i haven't been there before in my whole life. It kind of scares me.
And you know those weird feelings you get sometimes with people you meet? Sometimes you just get these really bad vibes off of someone, and you just want to run away. i think its your conscience that warns you about people. Once and a while i'll meet this new person, and my gut will start to feel sick, and i really dont want to be around them. I cant tell you why, but i will just get this weird feeling that they are no good. I'm not sure if that would be kind-of like deja vu? or maybe it is my conscience telling me who i should stay away from?
I honestly dont know.