How Am I Not Myself

"Every person is the creation of himself, the image of his own thinking and believing."

So, yes: this was the fortune in my cookie from the Pearl House today...but I thought considering my circumstances it was completely appropriate. Every person is the creation of himself...I'm finding it difficult to isolate the "self" in me. If I created it, I must have done a piss poor job. I'm not thinking or believing in much of anything anymore...guess that makes me without self.

My question: any thoughts on this? What defines us? I feel like a 3d grade writing prompt generator but HONESTLY. I need answers or at least directions so any perspective on the topic would be helpful.