Numb

I don't know why, but for some reason I just go completely numb from time to time. All my senses go to shit and my thinking, well... it's like a computer without enough RAM. Normal processes are unaffected but I can't do complex problems and my short-term memory is demolished. The first thing I notice, though, is the effect on my vision. I'm completely incapable of focusing on anything and the blind spot that every human has seems to double or triple in size. All the other senses are similarly affected. I can't hear as well, my sense of smell is shot, and my skin is numb. I don't know if it has an effect on taste. When it clears up several hours later I'm left with a crippling headache in the left part of my frontal lobe.

I know it's something physiological, though. My eyes work fine but the signal isn't getting processed properly. This stuff ever happen to any of you?