Phases Of Life... Is this all there is?

I think I've reached the stage in life where the only thought that comes to mind is "Is this all there is to life?"

Been feeling rather confused(that's another matter altogether), but also at the same point I just feel down... Don't understand it completely as to why I am feeling down...

Sat down for a few hours with a pen in hand and a blank piece of paper, trying to identify what's putting me down.... And nothing... Mind just went blank....