feel things have already happened

Its a common Phenomenon. Its called "Deja Vu" (pronounced Dey - zha- Woo) . Also called paramnesia ,describes the experience of feeling that one has witnessed or experienced a new situation previously! IM not really sure what causes it . But from what ive read this may result from an overlap between the neurological systems responsible for short-term memory (events which are perceived as being in the present) and those responsible for long-term memory (events which are perceived as being in the past).Studies are stil being done on this phenomenon.Yeah i get a lot of it too :-D

I think I understand what you said cause I do have that kind of feeling very often.