CLEARLY, you have a case of SEVERE claustrophobia. I have been claustrophobic my entire life. But my symptoms are restricted to enclosed spaces( crowded theaters, elevators, MRI machines, and airplanes). You are even more severe than me. Don’t bother with benzodiazepines…they work short term, and have a host of negative side effects. The only way that I know that helps is exposure therapy. It is difficult, time consuming, and can be quite fearful at first. But….THERE IS NO SHORTCUT…..you must get the right therapy from the right therapist. It CAN BE DONE. Good luck!