I have been lead climbing for only a couple of months. I was lead climbing for the second time that day an easy 5c route with a bit of an overhang, despite feeling already fatigued and without concentrating. I was focusing on clipping to the overhang quickdraw from a different and more comfortable position (stretching the arm to reach the quickdraw) but did not notice I had z-clipped the previous quickdraw. Trying to climb past it, I felt the drag and knew something was wrong but not quite sure what it was. I thought I had back-clipped (since it was the most common mistake, I thought about retracing steps and correct back-clip). As I started to fiddle with rope when the climbing wall manager shouted and told me to stop and yelled I had z-clipped. He instructed me to just hang on the quick draw that was correctly clipped and either come down or correct the z-clip below. My belayer couldn't see the mistake from where he was standing. It would have been a long fall had I unclipped from the correctly placed quickdraw (mistakingly having thought I had back-clipped it) and not having the rope in the right place in the quickdraw below.