Thanks for writing in.
From your information, it looks like your family had an occasion food poisoning
The bug which you are talking about could be in the intestines. All patients do not show the same response to a bug infection
. It seems that you had a more severe infection resulting in malena (to be confirmed after stool examination).
I suggest you consult your doctor and he will put you on antibiotics if you have still not started them.
Hope this helps.