Dream of building

I had a dream that I was walking around a giant building that I couldn't get in. I had a girl with and we were looking for a book. I finally got in and found the book but there was a party going on and the girl left and joined the party. I was envious of all of the people at the party. Then I found myself outside again without the book and I couldn't remember where I left it or how to re-enter the building and I kept going around and around only to find myself at the same place or facing more difficult obstacles