I noticed today that when I was photoreading a 1500 page book today, I could notice everything around me starting out, but, when I got to the middle of the book, I noticed that the only thing I was seeing was the book and I was only hearing the pages turn. Is this normal? I just kept going through the rest of the book. This is the first time that I've experienced anything like that before to, but, it's also the first time I've pr'd a 1500 pg. book too Thanks!