Songs are funny, in that some of the best ones look totally off, on paper. Even when you play a song in front of an audience, it is hard to tell how good it is, because performers tend to know how to get the kind of response they want out of an audience, using whatever they happen to have to work with.
Make a recording, and people respond to the superficial aspects of the recording--about the only way to tell is if it is any good is if it other performers have a lot of success with it--maybe not even then.

The trick seems to be that you need to believe in what you've written, regardless of what anyone else thinks, and to keep writing and pushing your stuff---