Ok, lets see if we can break this down.
1) You are not a failure, at times we all fail at something. What we define as very successful people fail many times before they actually get it right. They figured out how to learn from their mistakes and not repeat the same mistake over and over again. If you would read about Old Honest Abe, you would be amazed at how many times he failed, yet, he kept forming a new identity and you know the rest.
2) We all have identities, throughout our life we have many. A woman gets married, she becomes a wife, she has a child, she becomes a mother. These are just two examples of ones identities as we roll through life. Now a wife gets divorced, she is now a single woman, another identity.
3) We feel worthless when we fail at one of identities. We forget that we are more than one identity.
So, sit back and figure out what your new identity is going to be. Keep your resolve to become the person you want to be, remember, nothing in life stays constant, it either gets better or worse...I'd choose better...I bet you would too!