I'll just say it.  I've been in a rut.  

In my new role, though I think I am doing pretty well, I am experiencing the following:

Imposter syndrome is the condition of feeling anxious and not experiencing success internally, despite being high-performing in external, objective ways. This condition often results in people feeling like "a fraud" or "a phony" and doubting their abilities.

To counter these feelings, you might end up working harder and holding yourself to ever higher standards. This pressure can eventually take a toll on your emotional well-being and your performance.