My dd had a upset tummy and was sick several times early Saturday. Slept it off and actually well enough to go for a walk Sat pm. Fine Sunday and back to school yesterday. She came home from school looking flat but not feeling unwell but this morning had a bit of upset tummy again so I have kept her at home. The thing is she now has the most revolting burps (smell like dreadful fart) and we have not had this before. We don't normally get tummy upsets but is this normal??