HI, thanks for using healthcare magic
Persistent nausea and diarrhea should be assessed by a doctor.
There are different possible causes such as: (1) side effect of medication
(2)irritable bowel syndrome
(3)high calcium, kidney disease, thyroid disease
(4)
hepatitis,
gallbladder disease, GERD
(5)inflammatory bowel disease
(6)infections
To find out the cause, you would need blood tests such as electrolyte levels,
complete blood count, thyroid function, liver function levels,
creatinine (checks kidney), ESR (checks inflammation in the body)
Imaging of the abdomen may also be needed.
I hope this helps