Why does this happen for 13 years my body has been consists when it come to my period. I have always had a heavy flow and extreme pain to the point of being sick. Well then I move to Alaska and my period decides it's going to be light and only some times be painful. Then it decides now instead of always coming when it's supposed to it's going to come late for four months and always two days late then changes to coming early then changes to on time now I am late I just am tired of getting my hopes up/: