The first couple of times I saw the shadows, I passed it off as just me seeing things... but the more I kept seeing them and the more rapid they became... that's when panic set in and the feeling dread just was overwhelming.
As for the feeling of not wanting to drive up in the mountains at night... this wasn't our first time driving up in the mountains at night. Again, we pretty much hung out in the mountains like all of the time. We were regular visitors to Dock Flat, we'd go do dry ice bombs up there.. big bomb fires. There are abandoned mines up there, a ton everywhere and we'd crawl down into them all of the time.
My favorite thing to do was going up to Logan canyon and exploring Logan cave before they put the dumb cage on the entrance. Literally every single time we went to Logan cave was in the middle of the night. There is the old Indian school up in Brigham City, it's mostly gone now... but when I was in High School, nearly all of the buildings were still there. We would sneak into those in the middle of the night all of the time. There was one building that had a bowling alley in it... we'd go down into there all of the time. There is just so much stupid crap I used to do... pretty dumb dangerous stuff, looking back on it now it's funny but so stupid.
The day I mentioned in my story was different because of the prompting I had been getting all day from the moment I had woken up right up to when my friend suggested we go up into the mountains.