Surgery Coverage Denied!

Very bad news today.  Insurance called me and informed me that surgery is not authorized.  I will spend the next 2 days making phone calls, but it is very likely that surgery will need to be reschedule after approval is attained.  I cannot believe this is happening.  Everything is already set in place.  Flights and hotels are booked.  Family has taken off of work.  I've discontinued piano lessons with my students and packed all of my stuff to move back in with my mom.  Everything is planned around this surgery date.  I am officially freaking out, and I feel completely helpless at this time.  It will be up to my surgeon's office to convince my insurance company that surgery is a medical necessity.  I don't know how to handle this one.