It sounds like you were on your way to an astral projection. Astral projectors often describe hearing clicking when they reach the point where they leave the body. I am not certain of the reason behind this, but can say from experience that seems to be connected with astral projecting on this plane. Also, the solar plexus (a point more or less on the chest) is connected with the astral body leaving the physical. Some think that this is where it 'exits'. The numb sensation is one that I can also relate to. The 'numbness' is like the body falling asleep when all of these other things occur. We're basically leaving behind all of our sensations of the physical world, so the transition to this is a little like when we notice our foot is asleep.