Is it legal to demoted and take a salary away from a manager with no just cause ?

My concern is that I was removed/demoted from a managerial position. I was hired in a physicans office to be the nurse and also the practice manager. Approx one year later the physician I work for was approached by the company''s CEO and was asked to help with the cost of another practice manager that would be shared by 6 other physicians. The more physicians on board the more cost effective it would be for all involved. Approx 2 months later I was told that both salaries could not be paid and that I would be losing mine, to the sum of $12,000 a year. I have had no complaints or problems from administration or my physician to warrant such a change. This decision has caused a great deal of financial burden on my life. I am unable to cover my cost of living due to the drastic reduction in salary. My concerns have been met with negativity and misreatment by the parties involved, to the point of almost harrasment. Any advice would be deeply appreciated..Thank you, Jon. R