Welcome to healthcare magic!
You have not mentioned for how long you have been having loose stools.
Since the management of acute and chronic diarrhea
is different, I would like to know how long you have been having diarrhea.
But since you have mentioned that you have done all basic tests done, I presume you have chronic diarrhea.
Since you have night time diarrhea also, further evaluation is necessary.
You need test like upper GI endoscopy
with duodenal biopsy
for further evaluation.