Normalizing The Imposter Syndrome

"Imposter syndrome," or doubting your abilities and feeling like a fraud at work. 
- Harvard Business Review

Personally, I feel I am a self-confident guy. But recently, my hidden imposter struck me, just like many out there. 

A week ago, I sealed an international content writing deal that skyrocketed my confidence in my abilities. The client/CEO of the firm informed me that they would mail me the details of the first project two days after our meeting. 
Two days passed. Then three, then five. I followed up, as usual. No response. 

Did I charge too high? Did the client find someone else better than me? Did they think I don't have what it takes to provide quality content? 
These were some of the questions my mind started to throw at me. The hidden imposter in me made a grand appearance on stage. 
I was badly seeking some inspiration to get my thoughts back on track. 

Two days later, a notification popped up on my phone. 
"Very sorry, Sidharth, I was down with fever for the past few days. I'm mailing you the work details today." 
I told my imposter, "There's the door. Please clear yourself out."