No matter how “successful” you become, trusting yourself never gets easier. In fact, it only gets harder with more external noise and pressure. But you will never be happy with yourself or satisfied with your work if you don’t do what you truly felt inspired to do.
The more frequently you can confront and walk past emotional blocks, the more powerful of a person you will become. You’ll begin to believe in yourself, because you’ll have watched yourself act in a believable way.