The key word to remember is Environment. We are all influenced and affected by our environment. We associate different activities to different environments. When working from home we should have a physical space set aside for working hours, that is in some way removed from the space occupied in NON work hours.
If you sit in the same chair and face the same wall at work, as you do when you are relaxing and NOT at work, then the concept of being at work and the concept of NOT being at work, will blur and merge. Then people feel that they are never quite at work and never quite NOT at work.
Make your workspace different from your NON workspace, and rigidly enforce the rule that WORK is here and NOT work is there. Then the mind will have two distinct concepts and modes of thought that are associated to two distinct locations.