Danielle, have you had a tilt-table? If not, you could do a poor man’s tilt-table or get a heart rate watch with a chest strap or a Digifit Connect 2 for iphone, ipad, or itouch. Have you tried NasalCrom when your nose gets runny? Have your doctors checked your plasma catecholamines lying down and standing? What are your other symptoms when you crash? Do you have to urinate a lot after your “crash”? Does your crash sound like an episode of mast cell degranulation?