My energy has been unfocused the last few days. A slight touch of illness, a little gap between projects, a few days away.
It's so easy to let the momentum of a project slip away. It's easy to get bored with something that you've been working on consistently.
Taking a break to rest and to get away from your project is a good thing, as long as you remember to let go of anxiety about your project. It's a choice you can make, one which ought to be made consciously. Obviously you need to diligently work on your project to complete it, and you will complete it all the sooner for doing the diligent work sooner, but there is a place in the long process of writing a dissertation for taking a break.
The dissertation process typically takes months or years, during which the author is required to think clearly, work hard and write productively. Health, therefore, must be a primary concern. Both physical and mental health can benefit from rests and changes in patterns.
Given the value of maintaining a sense of enthusiasm and interest in the project, occasional time thinking about other things and getting away from the project (even if you do love it) may help give a little sparkle back to a project.
A little time away from a project also may help generate new ideas and new perspectives that are not so bound up in older thought patterns.
You have to be able to allow yourself that time, however, or there is little value in it. If you take some time away from the project and then spend that time anxiously worrying about the project and about your not working on it, then you're not going to get a lot of value from the time away--it will not be relaxing or restful; it will not be conducive to new imaginative perspectives.
Make it a choice: if you decide to take time, then let go for that time; if you decide to work, then work.