Hi.
Thanks for your query.
Read and understood your history.
You have explained this nicely.
You have a problem of
gastroenteritis , the intestinal component is so much that you are loosing precious fluids and electrolytes through the loose stools.
This may help the periods to extend as your hormones go into imbalance.
I would advise you the following:
First of all get the blood tests for : CBC, PCV, electrolytes,
Urine and stool tests.
Ultrasonography for the abdomen and pelvis, also helps for knowing the probable reasons for the extended periods
Get a course of an antibiotic,
Metronidazole, probiotic, symptomatic and supportive like Electral powder id there is no vomiting.
If the vomiting starts or is the
dehydration and electrolyte balance are too much you may need an admission to the hospital for a few days and get
intravenous therapy.