"Nervous Breakdown" is a non-mdical term of obscure meaning. But you could well be developing a Depression, a disorder which responds very well to proper treatment. maybe see a good local shrink for assessment and a discussion of your treatment choices.
Speedy is absolutely right about the great value of a break ( rather than a breakdown ) --- taking even a relatively short break away from the work-related stress, relaxing, footling round and taking it easy ; maybe devoting oneself to one of one's hobbies or avocations. I like his /her hobby, too, of "buy with the eyes", economical and satisfying !
But the other thing I think Speedy and yourself should then attend to, would be, possibly with the temporary aid of a psychologist, to assess the stressfulness of your normal job, checking out where stresses can and should be delegated to others ; where they can be made less stressful, and how you could pace the job as a whole so as to better preserve your strengths and abilities --- and to develop better stress management techniques so as to avoid reaching the point of cisis in the future !