Can I sue my employer for firing me due to illness, and long do I have to sue them before its to late.

In general, you can be fired for any reason at all in North Carolina. There is no law that says an employer is prohibited from firing you due to an illness.  The FMLA provides covered employees who work for covered employers with up to 12 weeks of leave for a serious health condition.  Not all employers and not all employees are covered by FMLA.  The serious health condition can be the employee's own or of an immediate family member. If an employee on FMLA is able to return to work in 12 weeks or less, then the employer must return the employee to the same or equivalent position.  Employees are also allow to take FMLA on a intermittent basis (here and there as needed).FMLA makes it unlawful for a covered employer to interfere with an employee's FMLA rights or leave or retaliate against an employee for exercising FMLA rights. That means that your employer would violate the FMLA only if it terminates you due to absences that are FMLA covered or in retaliation for using FMLA. If you are terminated due to an illness, it is possible that you have certain rights under the Americans With Disabilities Act (ADA) if your illness meets the definition of a disability under the ADA. The ADA prohibits discrimination against employees or applicants for employment due to a disability.  The ADA also requires an employer to provide a reasonable accommodation to an employee or applicant with a disability that will allow the person to perform the essential functions of the job.   Due to the complexities of the law, the protection the law provides to employers, and the fact intensive nature of the inquiry, the only way to determine if you have a possible claim under either law is through a consultation with an experienced employment attorney.