I am not sure but, don't know for sure..I would check human resorce dept, Do you work for a large company or small company? I would think as long as you have proof you should be ok, your obvsiously not faking. I hope your stones pass and everything goes good from here on out. How long have you been dealing with the kidney stone's? I feel it is no different then if you were in a car accident,,not your fault so how can you be fired? I think maybe call Dept of Employee right's or something look in the front of yor phone book. Good luck.