Talk to Gastroenterologist on Stomach, Black/dark Brown Stool

I'm having loose(not watery) dark brown stool since last 6 days. I visited a nearby local clinic, the doctor said it must be because of meat and he gave me his own medicine so I don't know the name of it. After finishing his medicine my stool color changed to yellow but today again it has turned to dark brown and still loose. I'm also having a slight pain under my stomach area and after the stool when I laid down in bed, some sounds were coming from my stomach like I was hungry but I wasn't. Kindly advise what to do.