There should be a word for the paranoia experienced after offering up one's personal creation for public consumption, the fear that actually you've been deluding yourself and it's truly terrible. It isn't lessened by the fact that you may have received a positive reception to stuff you've done before. In fact it's almost increased, as you worry about being "found out", that maybe what you did to get the praise last time was just a fluke, and you don't know what you're doing at all, really.
I guess the closest thing is that quote from Winnie-the-Pooh, which is something like sometimes a thing which seemed very thingish inside your head can seem quite different when its out in the open and has other people looking at it.