Exercise helps with anxiety, and it may have been the tennis that was using up all the extra adrenaline that goes along with anxiety. But.....we should never assume any new symptom is anxiety, and I would see a cardiologist for verification that all is well. This may not be necessary, but it's always better to be sure it's not more than anxiety. If your heart checks out okay, then "accept" this or you will continue to obcess over health issues, and you don't want that. You have been a healthy athlete, and are young, everything is on your side. See a cardiologist and then trust in what he says, and get out and live your life. Best wishes.
yes I have for 12 years I just answered the same question in a above post, your fine I broke down and got the tests done years ago it helps but not as much as you think going back to tennis or some sort of excercise is the best thing you can do, wish you the best