etvansego,
Hard to answer that question as the attitude toward preexisting medical conditions may vary from airline to airline. I'm not aware of any FAA requirement regarding F/A health status.
Have you been asked about your health in any F/A applications ? I'm not sure what one's disclosure obligation would be in that regard.
If your condition requires routine use of medicine, you might need to be concerned if those meds would show up on a drug test. That'd most likely be the end of your career.
What happened in the final-stage interview you mentioned...was it health related ?