If it's your first time working for yourself then you have some difficult lessons ahead, because firstly it's a lie. You are not working for yourself, you are working for your suppliers, current and future employees, your clients and the government. They all get paid before you do.
The big difference is you now get to live pre-tax which can be very exciting.
You need to develop routines and figure out what you need to be spending your time on as soon as possible.
If you are actively coding yourself, you will need to allocate time to biz dev and time to development.
Remember most clients are awake during the day so you will probably need to do biz dev in the day and develop at night.