Melancholy
What do you do when you realize that nothing you have ever done or said was original or even interesting? I guess you identify with the huge mass of humanity over the other .00001%*. So there's that to take some cold comfort in. And yes, I realized this at a much younger age, but that nasty ol' mid-life crisis has been punching me in the gut with it. Fortunately, I have my wife and kids, so I can't take this too seriously. But I could do without thinking about it.
*an estimation, based upon the number of zeros I was willing to write.