Why Am I Having Constant Menstrual Cramps?

I am a 45 year old female. My mother had menopause at 43. My cycles are approximately every 21 days; however I have had some occurring on day 5, 10 or 30. The current cycle started on day 43; however I had menstrual cramps for the entire time even though menses didn't start until day 43. I am currently on day 3 of my cycle and still have menstrual cramps. I was checked for endometriosis six years ago and there was none. Definitely no, PID since I have only had one sexual partner for the past 23 years. I am going to see a gynocologist at the end of the month. Is this normal to have constant menstrual cramps during perimenopause? Thanks.