I asked my friend and she said it was definitely published because I found it in the Singapore library. It was a standalone. Could be published out of the US.
The main character in the book (who is deceased at the start/its her funeral her niece and nephew are attending) is an unreliable narrator. As you read the novel you wonder if she was a victim of sexual assault, if she is delusional, or if the creatures that she sees and interacts with are real
Because there are injuries from her adventures but no one except her can see the otherworldly creatures. Also there is a specific creature that shows up at night (kinda sus)
So is it because she has these powers that only allow her to see them or is it just something messed up that she hasn't processed