Help! My tongue is BLACK?

Last night I had a really bad headache which i though was caused by getting my new PS3 :). So I layed down and fell asleep, numerous times through the night I woke up with extremely painful stomach cramps. I took some pepto bismal and went back to sleep. So I wake up, and my stomach still hurts really bad, so i get Tylenol and am about to take but i have a really bad taste in my mouth. I go into the bathroom ready to brush my teeth and my tongue is BLACK! It brushed away with the toothbrush but im wondering what is was from. The only thing I can think it from is helping my grandma. She had a fire and I was cleaning where it burned. Is it that what happened?