I have diarrhea as well as i [feel] constipated. i have the going and going... my stomach hurts -- and i think it's similar to what two of my friends had recently. i don't have a history of this sort of thing, however, i have had a peptic ulcer before in

Duration is key: The most intriguing part of your question is that two of your friends had something similar recently. To me that raises the question of whether you have an infectious colitis: parasite/Giardia, bacteria, etc. You need a stool culture after evaluation with your doctor. These symptoms can also be due to irritable bowel syndrome (which is common/your friends could have this, too!) Take care:)