I have spells available to my characters that come from this book but I cant find it listed in the sourcebooks. Cant even find it to buy it. I know its part of Princes of the Apocalypse, but I don't own that either. So where am I getting these spells from and how /where do I find this book?

The book is not listed as an available sourcebook for absolutely no good reason whatsoever. However, you have no need to purchase it, it is free content available to everyone and includes some spells and a few races & subraces.