I can not find a link to my book when I log in.
Hi, and welcome to the Community! 
I’m glad to see you’ve already found a solution here: Documents were there and then they weren't
I can recommend setting up backup copies for your book to be saved as well - here’s a quick video on it: Saving With Incremental and Automatic Backups
Let me know if there’s anything else, and have fun with Papyrus Author! 
