lose weight and you feel fine
You should likely also get checked for diabetes, as you are at increased risk and you episode happened after that sugar intake!
I think you definitely should go in and get your heart checked, a lipid panel as well and see if you need to start taking BP medicine. The mountain dew not only has sugar, it has caffeine which constricts your blood vessels and can raise your blood pressure & increase your pulse rate. I got the shakes once after taking my second prescribed cafergot pill for migraine (ergotamine with caffeine medicine). Anyhow, a young age is no guarantee you can't have a heart problem. Please go to the doctor ASAP!