pain in my intestines and pancreas area before my period?

I have a question regarding menstruation. I had the whipple procedure done 4 years ago, and had part of my pancreas removed and a part of my upper intestine removed.Ever since, I have had to alter my diet and avoid certain foods because it causes pain. I have been taking Nexium daily and buscopan on occasion before a meal for constipation. I notice that before my period every month I experience pain in my intestines and pancreas area. Is this irritable Bowel or pancreatitis? Why do I get this reoccurring pain every month? Is this due to swelling? Also, my husband and I would like to have a baby and wonder if it is safe? I wonder about being swollen and with my extended belly, will this cause more pain in my pancreas area and scar tissue and is being pregnant safe after whipple procedure? Thanks for your reply.