ECG queries

Ok this is a strange one and Im hoping someone may have experienced similar as its worrying me to death, I went to the doctor last week as i had crazy bad fatigue for the last month which is not like me so thought i may be lacking in something , i usually am at the gym most days, also I have been having an uncomfortable feeling in my chest randomly and other odd pains - she sent me for a routine ecg and some blood tests - on the day she said the ecg had 'changes' on it but wanted to show it to a colleague, she rang me last monday and said it has changes but she has no others of mine to compare it to, I had one done at Bupa a few years back and that was fine and so to be safe sent me to hospital for a ecg and a stress ecg , but at the hopsital , the resting ecg had changes again and they wouldn't let me do the exercise one, but the most worrying thing is the nurse said my ecg waves is what they would get from someone who is having a heart attack, at this point i was horrified, then she said but you don't look like you are having a heart attack !!! and that some women can show these abnormal waves normally which by this point i was totally confused and more than worried, she has ordered an echocardiogram but i have to wait 4 weeks for that , I am worried to death though , how come they didn't check me over there and then if it showed that ? , my blood results came back normal by the way - anyone know anything about this kind of thing at all ? Thanks Jo