Hii, so I read your story and I found it to be rather interesting. I think you could really push more into making use of the 5 senses(very useful when making a story on the paranormal and horror). For example, with where you character is handed the dairy, taking a moment to describe the sensation and texture of the dairy could emphasise its importance or how something is amiss with the book. And with scenes where things become creepy and eerie, really play on making great use of the 5 human senses - describe the odd flicker of old lights, unknown and unsettling figures lurking just within the corner of a character's eye, include smells like something decaying out of sight, or burnt wood to evoke discomfort and/or at least make scenes engaging. I also feel that the atmosphere could be further built with slow reveals to horror elements, let the unease simmer to deliver a shocking moment and also make subtle hints to the impending horror.
I also feel that the pacing needs to be slowed or have further space to let things breathe, letting those moments of suspense and horror build or let the viewer/characters process moments. And I also think making use subtext in this story could greatly help. Also maybe looking into other similar genres of your story and seeing how the horror elements/themes are used effectively could help with inspiration or understanding how they work and work successfully can help. Also playing around with the themes in your own way or putting an interesting spine on it for the story can help.
But either way, I can't wait to see what else you've got planned for this story.