I had the most vivid dream awhile ago, and in it, I found this really old book but I think the title was blurred, and it was really crazy because every time I would open it and read something out of it I got this feeling that I was like high or something and like that part of my dream was on repeat for what seemed like forever. It was just me opening the book feeling stoned and going right back to the start, and for some reason the next morning I felt like that was an actual book and I desperately needed to find it. can anyone tell me what this means??
Uhm, can you recall if there were any text in the book? Or if you saw any images or anything on it/inside of it?
Sounds pretty strange. 
Do you/have you done any drugs/smoked pot IRL?
I use too smoke IRl, and I often find myself smoking pipe in my dreams, epsecialy when I have smoked during the day. ^-^ And sometimes I get this stoned feeling in my dreams too 
It is quite natural… Your brain was creative enough to think out this book and, maybe, a page from it, but it was not able to create the entire thick book. So when you wanted to read on, the safest way to solve this situation was creating an infinite loop. The fact that you were obstinately trying to read it to the end made you think that it was very important, and the fact that you were unable to read made you think you were high… If you had never tried any drugs, you could have realized it was a dream, but this explanation became more realistic that moment… That’s what I think. But, as everyone here writes, only you can analyze your dreams.
I think there is a sleep period where you don’t make dreams with plot, but sort of concern dreams. They are repetitive, it seems that they often loop. Their theme can be mental concerns, mathematics, readings, administrative papers, etc.
It can also happen when you had an exhausting day, with a lot of mental work, (or play a long chess game for instance), etc. I don’t think the meaning is very important. Did you make a repetitive work the day before ?