What Could Cause A Pulsating Sensation In The Mouth And Gums Along With Exhaustion After Playing Tennis For A Short Duration?

The Hello Doctors, I want to share this strange feeling of mine when I sense a pulsating/beating in my mouth, gums, teeth like my heart beat after done playing tennis. Yes,I do really feel tired after 1 set of play. What does it mean that I feel very uncomfortable with this sensation. I m taking a bed rest now hoping it would subside. Thanks.