OK. This description is clearer than saying regular tarry stool.
When someone is passing black, tarry stool, the primary concern is that there is digested blood in the stool. When there is bleeding into the upper GI tract, such as the stomach or first portion of the small intestine, the blood is subjected to all of the acid and digestive juices of the GI tract, and will turn the stool black and tarry.
The most common reason for this would be either gastritis or an ulcer in the upper GI tract. This will often be an acid irritation syndrome as the primary problem, but it is also possible that it occurred secondary to another acute illness.
It is also common for gastritis or ulcers to cause nausea and vomiting, abdominal cramping, or bloating. And blood in the GI tract will tend to cause diarrhea.
There are other possible causes of bleeding into th upper GI tract, such as dilated veins at the junction of the esophagus and stomach, abnormal vascular growths, or tumor growths.
It is recommended that anyone with black, tarry stool should be seen by their doctor. However, until you can be seen, it would be reasonable to be taking a medicine to suppress stomach acid, such as ranitidine or omeprazole.
If I can provide any additional information, please let me know.