Audio pataje

About a year ago I pulled over on a dark highway because I was too exhausted to keep driving there were no streetlights no houses just trees and silence I locked my doors and set an alarm for twenty minutes a few minutes later I woke up to tapping soft slow deliberate it stopped when I opened my eyes then it came back this time from behind my car I checked the mirrors and saw movement near the trees like someone stepping back then I heard something dragging along my car I did not wait I started