Six days ago I was a little hungover, took a drag of my cigarette, and instantly felt like I was going to pass out. I ran in the bathroom and my heart was racing for almost a half an hour. I had shortness of breath, and was trying to calm myself down but failed. I finally told my fiancee to call an ambulance. After almost the whole day in the er, and after an ekg, blood tests, and chest x-ray, the diagnosis was dehydration. I didn't understand that since I had 4 bottles of water that day, but I did feel better and went home. I thought everything was over. Wrong. Since that day, I have had shortness of breath, I get light-headed, ansy, and sometimes my throat feels tight. I also have not smoked since that day. I went to my doctor who made me wear a heart monitor for 24 hours. She thinks I either have anxiety problems or some sort of heart palpitation problem, like mitral valve prolaspe. Has anyone else had these symptoms? I am freaking out wanting to know what I may have. By the way, I am 23.