Can I be fired while on medical FMLA

Yes, you can be fired while on FMLA. The legal issue is whether you can file a legal claim relative to the firing.  North Carolina is an employment-at-will state where an employee can be fired at any time for any reason. The only time you can file a wrongful firing claim is when you can show that there was an unlawful motive behind the firing.    In this situation, if you engaged in misconduct before your FMLA and are truly being fired for that misconduct, then there is no wrongful firing claim.  However, if your FMLA leave itself is the reason for the firing, then you will have a legal claim.