I recently stumbled upon a great website where you can download dozens and dozens of books in Spanish for FREE! And about all sorts of topics, both fiction and non-fiction. I highly recommend it if you are looking for stuff to read in Spanish.
Here's the address:
https://espanol.free-ebooks.net
You need to register first, and with the free account you can download 5 books for free every month, so that's plenty to keep you busy, I would say!
They have books about self-help, fashion, religion, health, cooking, animals, cooking, photography, fiction, sport, you name it!