Even a lifeless tree can be useful, it is capable of producing mushrooms and firewood.
You might have failed and fallen but that does not make you good for nothing, there is something useful in you.
With positive mentality and unshaken zeal, you can be productive even in your seeming hopeless and useless state.
People may discourage, underrate and condemn you but you will be useless and relegated only when you allow their comments to dictate your pace and destination.
Keep on, you are still valuable, never let your darkest moments suppress the value and the potentials in you.