An employee who is discharged, demoted, suspended, threatened, harassed, or in any other manner discriminated against in the terms and conditions of employment by his or her employer because of lawful acts done by the employee on behalf of the employee or others in furtherance of an action under this Act, including investigation for, initiation of, testimony for, or assistance in an action filed or to be filed under this Act, shall be entitled to all relief necessary to make the employee whole. That relief shall include reinstatement with the same seniority status the employee would have had but for the discrimination, 2 times the amount of backpay, interest on the backpay, and compensation for any special damages sustained as a result of the discrimination, including litigation costs and reasonable attorney’s fees. An employee may bring an action in the appropriate court for the relief provided in this Section. The remedies under this Section are in addition to any other remedies provided by existing law.