“Fireflies” in my vision and then peripheral movement are the two effects that hit me first, usually around 24 hours.

I will often hear what sounds like voices from another room. The first time this happened I freaked out a bit, searched the entire house, peeled outside through windows. When it was clear, I put my ear close to my radio thinking it was on at a really low volume. But of course no matter what I did the sound stayed the same. Then the irrational state of my mind lead me to believe the house was haunted.