Saving Bug

My Character was idled up against a fence [Top Image], under a Wooden Plank in a abandoned mineshaft, I took a break, so i saved and quit my world, and upon loading it back up, I was at the surface, generally close to where I was standing though. [Bottom Image]

Upon repeating saving and qutting up against the fence, it once again put me back at the surface, but a few blocks away from the last spot.