not a founder,
but I would start with building some peace of mind for yourself -- Journaling, mindfulness, meditation, prayer or similar is a great place to start and most high-productivity folks actually draw a connection between this sort of focus and both increased productivity and lower stress. In your one-man-band phase, this is super important for you to constantly improve.
A less popular angle is to cut out alcohol. There are huge gains to be made in focus and rest without it.
a good reference for this is The Productivity Project available in audio ( I listened to it myself )