I would get another appointment with this doctor and inform him that if you were having panic attacks than the medication he gave you should have help you by now and you are still experiencing symptoms. Request that he order a perfusion stess test, which he probably would have ordered in the first place if you had insurance. The other route you can take is when you have the next episode, than get yourself to the nearest emergency room. They can perform an ekg, blood work and hopefully admit you for a day to perform the stress test and a cardiac ultasound to rule out any cardiac blockages. Make sure that you request a perfusion stress test, this test gives more information than the standard stress test. The hospital can not refuse to treat you because you do not have insurance.