Am I protected from being fired unjustly?
As the employee, you are in the best position to sense whether or not your rights may have been violated. There are a number of federal laws, as well as state laws, that protect an employee from being fired for reasons such as race, gender, nationality, religion, color, age, or disability (see also Job Discrimination), as well as certain behaviors, such as being a "whistleblower" or refusing to violate a state's public policy. You may have an express or implied contract that you will not be terminated from your job except for good cause. There are also some laws requiring notice be given to employees before large employers may close plants.
If you suspect that your rights have been violated, you will definitely want to consult with an attorney who is familiar with both federal and state statutes that protect you.