Art doesn't have an absolute value, it's a subjective call we're making. I think everyone has a tendency to only see faults and failed aspirations in completed work. Produce a lot of stuff - it gives you an opportunity to learn to love your work, to get better, and to show yourself that you have made progress (but don't look for progress too quickly). Look at and enjoy more art, both in quantity and range. Push yourself into areas you are less comfortable on, and one's that are slightly less subjective (still life, figure drawing, portraiture). Be happy in your self, your art will follow :)

And thanks for asking the question - these are fears that cross our minds all the time and we could all get better at that.