[barrysaunders]

Do a detailed post-mortem, ensure you can learn from it. Remember that the correctness of a decision is about whether you made the right choice with the information you had at the time, not whether the project succeeded. Many projects succeed in spite of poor decisions, not because of them. If there are things you could have done at the time to improve the chances of success, acknowledge them and ensure you do them next time.

You have a good track record, so do not feel bad about one failure. No-one succeeds every time, and the occasional failure is necessary to ensure we learn how to deal with adversity and become more resilient.