Answer:
Diane is most likely suffering from generalized anxiety disorder (GAD).
Step-by-step explanation:
Generalized anxiety disorder is a mental state that leaves a person feeling anxious and unable to concentrate on any work. It is also characterized by a constant state of feeling worried about a number of things and overthinking about issues ranging from finances to family to other issues.
In the case of Diane, her inability to relax even after work, constantly thinking about work, or worry about home while at work are all signs of GAD. It not only makes her anxious and worried about things but also leaves her sleepless at night.
Thus, Diane is most likely suffering from a generalized anxiety disorder or GAD.