Pre-menopausal or should I be concerned?

Ok, little background first. I'm about to turn 45 and a little while ago my mom let me know that she started going through menopause when she was 48. Since I had kids, almost 18 years ago, I have been pretty regular, give or take a day on either side of my expected due date. Last month I was a week late starting my period and I had some of the worst PMS symptoms I've ever had. My breasts and nipples hurt for two weeks solid. This month I'm two weeks late and when I finally did start my cramps are so bad I'm beginning to wonder if I'm not giving birth again. Is this "normal" type stuff for being pre-menopausal or should I go to the doc and get things checked out?