Upgraded iOS on iPad, through iTunes on my pc, and now can't find some documents(pdf) and several books

Over the weekend, I did the upgrade from 7. to 8.0.2. I didn't have enough memory to do it standalone, so I hooked it to iTunes on my pc and did it that way. But now, I am missing a number of document files (pdf) and half a dozen books. I was looking on my pc, but I don't know where to look to find them. I also wondered how I could look what's in the iCloud, because it backs up every night. They ought to be there. A little help, please??