I was symptomatic for 13 years and was just diagnosed in May of this year. Best advice-find a cardiologist and ask for a POTS evaluation. That may look a little different depending on the doctor, but mine was an ECG (sonogram), Holter Monitor for 14 days, and a Tilt Table Test. In the meantime, keep a detailed journal of your symptoms. The ECG will look for any abnormal issues with the structure. And the monitor and TTT combined will give a detailed profile at how your heart reacts to the changes that occur when you move. If you have more specific questions, please do t hesitate to reach out. All of my tests were done in March & April, so it’s all still fresh. I would be more than willing to help you anyway I can ❤️