Getting Fired for having Mental Disorder

So I started working at Mid Atlantic Retina about a month ago and they I was asked to travel to long distance locations from medical office to medical office I refused due to my mental condition and was asked to provide paper work by my doctor which I did I made an appointment with my PCP and she signed off on the fact that I can't be traveling due to my Panic Disorder and GAD so I submitted that paper to HR of Mid Atlantic Retina and they have fired me 2days later saying because of my Illness and not being able to travel I can no longer be employed. Having my conditions is hard as it is and being told you not good enough because of something that's not my fault felt even worse, it's like telling cancer patient or employee you can't work here you have Cancer!!!