Stomach bleeding after the master cleanse?

Hi all,
I just tried The Master Cleanse for the first time and got through 3 days. I did everything as recommended, making the recipe down to exact measurements and having laxative senna tea in the evenings. I just got off of it this morning. I had a banana and some grapefruit juice for breakfast and organic tomato soup (with a few tortilla chips) for lunch. What worries me is that right after lunch I had to use the bathroom and my stool came out dark and blackish. My stomach is also now hurting, I have the feeling of having overeaten (although I actually ate very little). I'm a little scared of going to the doctor about this. Could my stomach be bleeding? Did I give myself an ulcer from all the lemonade? Or is this just an effect of the master cleanse...maybe I ate too much?

Thanks.

Update: also experiencing sharp, sudden stab-like pains around my lower right abdominal area. I basically keel over when it suddenly hits...now I'm really worried! Tweet