Fred, I'm so sorry, but perhaps this is really not serious

There are many causes of inverted t waves aside from myocardial infarction. Transient ischemia can do it, but also electrolyte imbalances, dehydration, anxiety and stress, drugs, heart block (a type of arryhthmia), and more. You will need to get it worked up to try to find a cause. There are other tests they can do to see if you indeed have had a cardiac event.

Good luck! Please keep us posted.