Hello, thanks for using HCM.
loss of appetite, weakness and sore mouth are general symptoms which indicate that the body is not well. There is a wide range of illnesses that can associate the general symptoms together with stomach (abdomen) disorders which could be categorized into infectious, food related, surgical and extra GIT pathologies. Infectious causes include; -gut flu: which is viral borne and could present with abdominal pains, diarrhea
, subsiding after a few days and treatment is usually re-hydration, - bacterial infection: usually with fever, abdominal pains and vomiting and diarrhea. Food related problems include constipation
, food allergies which cold present with vomiting and diarrhea usually after a particular meal, food poisoning
etc. Surgical causes could be appendicitis
, organ perforation, occlusions etc.
In her case, its uncertain to say what might be the cause of your problems due to the limited symptoms you gave. However, abdominal problems in children range from mild causes to severe and lethal causes without much difference in the intensity of pain felt. So, i will advise you see a doctor for an evaluation and possible tests at least to be sure of the condition.