As someone who had POTS for years and was misdiagnosed, you can easily check for issues with your heart rate or your blood pressure at home. Get a spo2 finger reader at the local pharmacy, and get a blood pressure cuff reader. The kind that goes on your arm are more accurate. Read the manuals and understand how to improve accuracy with these tools before proceeding.
Take a few readings with both while you are sitting comfortably after resting quietly with feet uncrossed and not talking. Rest your arm at heart level with a pillow. Average the readings.
Stand up. Immediately monitor your spo2 , and heart rate. Take a BP reading.
Continue to stand in place. Take readings every two minutes for ten minutes.
If your spo2 dips a lot, you need a cardiologist. If your heart rate dips or increases a lot, and stays increased or decreased by 30 or more points, you need a cardiologist, if your blood pressure drops significantly or rises significantly and does not stabilize after ten minutes, you need a cardiologist.
This is the poor man’s tilt table test.