I know this is not due to cramps but on the first few days of my period it hurts immensely to go poop! I find I need to grip onto something just to go to the bathroom. I can't stand up straight or walk, it happens with gas too. I can't sit up or sit still in school due to the pain of gas. What is this pain? I'm a seventeen year old girl in a lot of pain. Please explain what's going on!