I usually feel okay about finishing books/series, only suffering from book hangovers on an odd occasion, but damn… When I finished my WIP a few days ago, the last book of The Light of Darkness, I ended up with the worst case of book hangover I’ve ever suffered 
I’m so upset I’ll never write about these characters again!!! 
I love them all so much, and I’ll miss them like crazy!! 
But… Yay me, for finishing the book, I guess 
