Low Cortisol Levels and Confusion

So I recently found out my cortisol levels were dangerously low. No idea what triggered it but at the time had been in hospital for months following a variety of illnesses (in particular severe sepsis causing liver and kidney damage; gastroparesis / intestinal failure resulting in a jejunostomy tube for feeding, a venting PEG and parenteral nutrition; bouts of dehydration, hypokalaemia and hypotension). After a few months on Hydrocortisone stopped medication for 24hrs then has a short synacthen test. Somehow passed that so was told to stop Hydrocortisone permanently. Ended up back in hospital with low BP that couldn't be raised with IV fluids and reduced consciousness. Dr's ended up administering emergency Hydrocortisone injection which worked. Had a repeat 9am cortisol which again showed dangerously low cortisol. Long story short does anyone know why I might have passed the short synacthen test despite obviously having some sort of cortisol deficiency? Endocrinology wonder whether it could be related to my intestinal failure but haven't seen anything like it before. Very confused, any advice would be appreciated