Hi, I have been experiencing sharp knife like piercing pains in the lower part of my stomach, generally a week before my period, on and a week after, i was on the pill and left in 2007, ever since then the pain has started, it has now become even more painfull then before, its worse when i go to the toilet, i am unable to go out as the pain gets so bad that feels like my entire lower stomach is going to pop out. What could be the cause?