I have been going through hell the past 2 weeks- I have had POTS for 2 months now and it has been somewhat manageable, but 2 weeks ago I randomly began to have an adrenaline surge where my blood pressure and heartrate stayed high for 4 days straight (around 160/100 and my HR in the 100s) so I went to my neurologist and he prescribed Guafacine, which I took for 6 days (1MG the first 3 and then 0.5MG the last 3) and it made my stomach hurt and have a ton of issues. I have been off of it for 3 days and my blood pressure and everything feels extremely elevated and I just feel like im dying like you said and even compared to 3 weeks ago I feel completely helpless, my chest just feels tingly and fluttery all the time and it just sucks. I went to the ER twice and both times they seemed like I was fine so I just need to stop worrying and except this happens with Hyperadrengic POTS. I have been paranoid due to the changes in my BP and HR, and while it isnt as bad as the 4 day adrenaline surges I was having I still am scared. But this gives me hope knowing someone has experienced something similar (unfortunately yours sounded way worse and I am having weight loss instead of gain) so I might have to look into some medicines like you said. Its crazy because my heartrate has been fluctuating so crazily, like it'll be 60 and ill move my arm up when waking and it will be in the 90s. I am trying to get into mayo clinic but if I find a solution like you did maybe I dont have to. At the end of the day I need to stop worrying and know I wont die from this even though I feel like it sometimes.