Hello everyone. I was diagnosed with POTS around 16 yrs old. I have been underweight my whole life. I have not gained any weight since being diagnosed with POTS- I am now 20. I do sometimes suffer from a lack of appetite, but there have been other times where my appetite has been good or even elevated. I have never been above 90 pounds and I am 5 ft 2. Currently I am 85 pounds. My lowest weight was 81. I honestly want to cry, and I am so scared. My POTS has gotten so much worse since I've been at this weight. If I calculate my BMI, that puts me at 15.5! Does anyone else suffer from a very low body weight? I was thinking that since my heart is always going fast and my body is generally working harder than others, it would burn more calories. I am fed up and would appreciate any advice I can get.