you had flu
like illness for few days.
sometimes after common cold/viral fever
abdominal discomfort may occur due to various reasons.
here you should mention about your age,sex,you had fever or not,other medications you took for flu.
specially medications are very important as some antibiotics can cause a type of colitis(abdominal inflammation
) if taken for long.
imodium(2mg tab/cap available.probably you've taken it) is a drug which decrease stool frequency BUT has many limitations of use.
specially in infectiosus causes of diarrhoea
as it reduce gut motility chance of flare up of infection is there.
so 7 doses of the drug in 36 hrs in diarrhoea after flu was not proper.
NOW you have black stool
it may be 'malaena' indicating g.i. bleeding.
YET i'll advice you not to panic as it is managable.
please consult your family physician as early as possible.
get well soon.