what it sounds like is that you are having anxiety
or panic. those symptoms are totally normal for a anxiety/panic disorder. you may be short of breath or have a racing heart but those are common symptoms of anxiety. i have those symptoms all the time. it is very scary at times but it will pass. just go to a quiet place and try to relax. these things can come out of no where or can be brought on by certain triggers "public places or when you need to be alone"... many people have this disorder and dont even know it. go onto yahoo and type in "anxiety symptoms" and you can check it out and try and diagnose yourself. well, actually.. you should ask your doctor to do that but just ask her if this is something you might have. im almost positive it is what you have going on though. best of luck!!!