Heart palpitations upon standing or going up the stairs, anxiety, and lightheadedness after an almost fainting incident in a hot shower months ago. i havent had an incident since. blood tests also came back all normal. what should i do?

Blood test does not replace a thorough physical examination and detail medical history. Hot shower can lower blood pressure so I guess your symptoms are due to low blood pressure with standing (orthostatic hypotension). You need to be examined by an internist or a cardiologist. In the meantime, you can try to combat the symptoms by increased fluid intake with salt containing drinks for athletics.

Check your blood pressure on going from sitting to standing to see whether you're experiencing postural hypotension which can be treated. Wear an outpatient heart monitor for 48 hours or longer to determine whether your palpitations are due to true cardiac arrhythmias or whether you're having inappropriate rapid heart rates with normal activities. If tests are ok, consider stress management thera