When that happened to me, it was my gallbladder. You didn't go into details, but, for me, I would be fine in the morning till I ate something then I would feel bad all day long, with vomitting and diarrhea.
Another thought, could be your blood sugar. Are you eating a protein snack before you go to bed?
Another thought, could be your blood sugar. Are you eating a protein snack before you go to bed?