"How" you went from being number #1 to being a "nobody" is really hard to answer. As you probably know, sales is the type of job that is bound to have large upswings and downswings. So "how" it happened is less important than the "what". Meaning, what will you do next? The internet is full of great quotes on failure and they all say sort of the same thing, "this failure is a stepping stone to your next success."
In therapy, we look at what you can learn from this moment so you can move forward and find the next success. The simple truth is that you have a choice, let this feeling of defeat make you feel like a nobody or figure out what it takes to get back to where you want to be.
Some questions that come to mind are: Has this happened before and how did you pick yourself up again?What goals can you make to stay motivated and get better? Are you really a nobody now, or just not number one?
Its easy to feel like a nobody when we aren't at the top. Challenging these types of beliefs about ourselves is really important for long term success. A therapist can help you reframe this moment as a stepping stone, get back in touch with your strengths, and set goals that are attainable.