I used to follow witchcraft/wicca as a child. My biological mother is very into it and swears by it so naturally I was intrigued growing up.
I studied tonnes of books- old, new, dummy guides, everything i could get my hands on. Over time I noticed that in the earlier years of paganism and the Wicca religion, it wasn't about the witchcraft we know today that casts spells on people and has powers. It was about being one with nature and using the natural power from the earth to heal, pray and carry out rituals.
I do know what you are talking about with the deja vu, happens me all the time. Always has. I can honestly say that after spending ten years looking and hoping for some sort of real witchcraft, I found nothing. I don't think what your experiencing is anything to do with it.
Some people can just pick up on certain things subconsciously and they can read people well without even realising their doing it. I think you might be falling into that category. an aunt of mine would always be able to tell if someone was ill or sick before they even felt the symptoms. she wasnt a nurse, had no medical experience, and yet, she knew when people were falling ill.
I hope this helps. Here's a site I think you should look at: