I would almost guarantee what your friend has is hEDS (possibly with ME/CFS which is chronic fatigue), including MCAS (severe allergy issues) and gastroparesis (paralyzed stomach, fairly common to co-occur with these conditions.) That's just the beginning of all the issues hEDS can cause, and it's fucking infuriating, because people like you AND medical professionals both don't understand and sometimes don't believe our experiences are real.

How do I know? I have them too.

Being disbelieved by medical professionals and friends as my body was failing me literally almost killed me. If you can't be a better friend, just get the fuck out of her life.

If you confirm she does have hEDS and you want to be a less shitty friend, I highly recommend reading Disjointed edited by Diana Jovin to get an idea of what she's experiencing. It is very much real, not actually that rare, and very poorly understood.