Menstrual misunderstanding?

So my period was 2 days late according to the eve (usually I’m pretty aligned with the dates it gives me) and my period seems a little wack this time. I normally get cramps exactly one week before my period, none this time until about the day before and they were excruciating, which again is not usual for me. But get this, I get my period and it’s super heavy. One day later, I’m finished bleeding now it’s just brown discharge. My period has always been 5 days long since I’ve gotten my first period, and this has never happened to me. Any opinions?