via Elad Gil:

Many first time CEOs feel that they are screwing up or failing on a regular basis. This is driven by circumstance (you are thrown into new challenges every month), the difficulty of running a startup, the need to build an executive bench, and a lack of perspective. By building out an executive layer, pursuing 360 feedback, and getting sleep and perspective, you can mitigate these feelings of failure and focus on the task at hand.

There is a lot of great advice here.