As a working artist, I too would like to point out that art is all too often defined by what we as individuals are programmed to believe what "Art" is. I too have my off days. I also dislike the closed mind of the garden variety "critic" and its all too easy to push yourself and your work to reflect the wishes of people you may or may not know.
Let your work reflect what is within you. tap the source that tells you what is pleasing to the ey and hand. try to understand forms as they are found in nature and understand ergonomics. dont push. if you feel something lacking. take a breather. just remember your mission is to create a work that brings beauty, and purpose in its viewing or use.
all too often i hear from people, that they cant draw a straight line, or think like that. but really we all can create as easily as we destroy.
stay true arch. youll get there.
best of luck M.