Panic Disorder

It sounds like you're experiencing something scary.  Based on what you've described, it sounds like you're experiencing a panic attack.  Feeling the earth moving in a public place is a symptom of agoraphobia.  I would strongly recommend you see a therapist for individual therapy to talk about these symptoms and try to learn coping skills for what you're going through.  Since you've already been seen by a physician that can rule out other physical abnormalities, a therapist could help you go further and diagnose other possibilities.  If you're in the Los Angeles area, I would be happy to help you: www.drlanichin.com or you can find someone else closer to you.  Your physician may also be able to refer you to someone.  Good luck.