I would recommend for you to read and implement the organization/productivity system from Getting Things Done by David Allen [0]. It discusses essentially your main problems of dividing up your life into projects and timing yourself. The system also includes sections for putting some of your ideas in an 'Incubate', basically putting it off for another day once you get through what you have. Having a running list of all your commitments and projects like the system does I think will help you to analyze your time usage and realistic expectations for your productivity and stuff you want to engage in.
[0] = https://www.amazon.com/Getting-Things-Done-Stress-Free-Produ...