Another period question for the ladies...?

I have always had super regular and pretty light periods. They came like clockwork. Last year I had an IUD put in and then taken out 6 months later (it was the Mirena and it was making me sick) After that, my periods were kind of normal. They pretty much came at about the same time but they got real heavy. Then they started to come either a few days early or late. This month I felt the cramping a week early, then my period came a few days after it should have. It only lasted maybe 2 days this time, and was heavy the first day and light the second. Normally it lasts about 4-5 days. Anybody else go thru this? I will be going to my doc for my yearly, just figured I'd ask.