Stomach bug?.....these are my symptoms?

Since saturday after noon i have had this bug of some sort i can only explain it as having diarreah cramps but times 10, at one point when i was taking a nap from being so ill with this i had to curl up in a ball and cry because it hurt so bad, its like a tight burning pain.... now a few days later (monday and tuesday) i have just had what feels like a hungry tummy feeling, you know like when it grumbles but i have diarreah and my stool is very very very dark, no blood but very dark, the only thing i was taking was pepto... i also havnt eaten anything since saturday but very little, i get very sick from it.... should i go to the drs? what could this mean?....