You do very well when you have a project with a start and end date. For example, with your first book, you were able to bring tasks to completion with ease and wake up crazy early to do them. You were motivated not only by the beginning of something new but the prospect of finishing it so you could start another project.
At work, you have some new plans, and you seem to be happier because those tasks are definite. They have direction and even a start and end date. You can see the end vision even if you don’t know the full impact it will have, which is okay!
Always give yourself a project, at least where it’s appropriate. For example, people are not projects. You should not treat them like some sort of puzzle or intellectual challenge—they are people. Obligations don’t have to be projects, either. Laundry is very simple and takes no more than five minutes of effort at a time—why turn it into anything more convoluted? Even your writing practice doesn’t always have to be a project. You could give yourself writing prompts that are detached from the rest of your work and seem to have no significance rather than being connected to some overarching task. Or, you could frame a daily practice as a project, as you have with your reflections project. (Who are you writing those to?) Perhaps you could practice creative nonfiction by writing ninety days of stories from your day-to-day experiences. That would make a small task a project and possibly easier to achieve. No matter what you choose to do, know that you do well with projects, so take advantage of that even if it’s a psychological ploy to make you focus.