Your mission on earth is not complete
If your still alive your mission on earth is not yet complete. People are happiest when they are so completely engrossed in an activity that they lose track of time and go into what is called a flow state. For this to occur, the activity must be reasonably challenging, neither too easy or too hard. It must be something that is of value to others, and it must be something that you love, that you can be passionate about. Your passion for your work will get you out of bed and into the workplace' even when you don't really feel like it, even when you are discouraged about your progress.