Nightmare Time

So, I've been writing down my dreams for quite a while.
I usually write short notes on a piece of paper right after waking up (provided I remember the dream well enough) and then write it in a book some later time so I can focus more on getting all the descriptive details in.
For each dream I also write down a title at the beginning so I have a sort of table of contents. I'm mostly able to remember what dream it is by looking at the title as it's something that stood out in that dream or because it's the general theme of the dream.
A few days ago, I wanted to look up one of my dreams to confirm something. I found it right away as the first entry, confirmed what I wanted to and then looked through the other titles for nostalgia's sake.
That's when I noticed one title simply saying "Nightmare" on page 111. Nothing else. I was kinda amused, wondering what kind of nightmare it had been for me to only write down this one word. I was like "Oh let's take a look at that, I wonder what kind of horror that was. Some emotional terror? Some jumpscares?"
When I got to the entry, I only read the first sentence and immediately recalled the whole dream. My first reaction was to look away from the booklet, closing it and exclaiming "Oh fuck no. Why...". It wasn't any emotionally painful dream or jumpscares but rather the kind of silent dread that something is very much not right and that I'm in grave danger, then people acting weird and getting threatening.
I was kinda amused after accidentally remembering it, though I was actually somewhat frightened then, or at least more alert, like after watching a horror movie.
It didn't help that I did that just before going to bed and I was kinda laughing at and cursing myself for naively checking the entry simply titled "Nightmare", probably to avoid myself casually remembering it.
Or maybe I was like "Hey I bet I can make myself remember this some time because I'll be too curious to find out what this obscure title means."