Thank you for the query.
Upper middle abdominal pain
(if that is what you mean by stomach pain) can be caused by food poisoning indeed. So is diarrhea
and headache. Most of food poisonings
are caused by viral or bacterial infection and do not need medical attention. However if diarrhea is present longer than 48 hours doctors visit and stool tests are necessary.
Swallowing lots of blood from nose bleeding can also cause diarrhea. In such case, the stool should be black.
If your symptoms are getting better, no need to consult this case with a doctor. But nose bleeding should be checked by laryngologist.
Hope this will help.