I had this experience, after a couple of months of working out really hard in what was my first cycle after a career in running and bicycle racing, I had made some nice gains adding 100lbs to my bench and taking a lot of fat off, my waist got really small. I decided to shave my chest and looked in the mirror and was like "holy s---" I thought I looked really good. 2 months later after the scale and tapemeasure and increasing max lifts even more I would look in the mirror and wonder where that other guy went, the one I saw in the mirror 2months before. It was clear I was leaner and stronger but I couldn't see it in the mirror.