I was terminated for missing to many days while going to the doctor about my seizures and mental illness. Do I have a case?

It is impossible to tell from these facts. In general, an employer in Tennessee can terminate you for any reason including a health related condition or missing work due to a health related condition.  However, if you need time away from work, and are eligible FMLA, then the employer must allow you up to 12 weeks of leave per 12 month period.  If you were FMLA eligble, and you were fired for absences that should be FMLA covered, you would have a claim.   Additionaly, there is another law, the Americans With Disabilities Act (and the Tennessee Human Rights Act), that prohibit discrimination on the basis of a disability and requires an employer to provide reasonable accomodation for employees who have disabilities.  One accomodation that is sometimes possible is time away from work even if the employee was not eligible for FMLA. These are complex laws and each situation is different so you really should consult with an experienced employment attorney.