You Are Not Your Thoughts
Keep in mind that you are not your thoughts.
This is quite similar to Imposter Phenomenon or Capgras Delusion, both of which are frequently referred to as Imposter Syndrome.
You must reach the point where you believe - without a doubt - that you are good at what you do and deserve to be recognized for it. And you must think that it is acceptable for YOU to give yourself credit.
Keep in mind that you are not alone. Everyone suffers from imposter syndrome.
Recognize that no one truly knows what they're doing. As they go, they make their best guesses and try to learn and develop as rapidly as possible.
Remember that a thousand miles begin with a single step and that any progress, no matter how slow, is vastly faster than no progress at all.
Recognize and appreciate the task, intellect, and insight that led to your accomplishment. You may even be able to take action if you recognize that the reason you feel fraudulent is that you are new to a task.