Hello
Long standing tampon inside vagina can lead to infection or inflammation of the vagina as well as urogenital tract.
In my opinion you should take hot water bath and drink plenty of fluids daily which will help by flushing off the urogenital tract, if it doesn't help than you may require a course of antibiotics under medical supervision.
Loose stools might be related to acute
gastroenteritis or
food allergy.
I wodu advise you to go for
stool test for ova, cyst and Protozoa, you may require ofloxacin or ornidazole group of drugs or its combination.
Drink lot of water , ORS solution and fruit juices it counter
dehydration and
electrolyte imbalance.
Curd, yoghurt will definitely help you .
Maintain good hygiene, wash your hands every time you use washroom.
Hope I could answer your question
please feel free to ask for follow up question, I will Happily answer you.
Best wishes