Hi Warren81,
It is time to see a doctor. That is a long time to have diarrhea and you could be dehydrated and lose electrolytes. Can you eat and drink ok? You may have picked up a parasite, bacterial food poisoning or perhaps viral (but they don't usually last as long). You need to get tested very soon. If you haven't been drinking you need to get into an ER but if you are able to keep fluids down go into the doctor right away. How often do you have diarrhea (how many times a day)? In any case it has been far too long. Please let me know what the doctor says. There are other reasons for diarrhea, such as some drugs like Prilosec can give you diarrhea but not usually stomach pain. Also, if you had antibiotics such as clindamycin you could get another bacteria that causes diarrhea that needs a different antibiotic and soon. Also, sometimes you could have an intestinal problem such as Crohns disease or other GI problem it depends. If it came on suddenly especially after eating or travelleing or hiking and drinking water from a stream or swimming in potentially contaminated water all these could give you a bacterial or other as above. Black stools are when you have blood in them so the green stool, not sure.
mkh9