Long AF

I'm currently on day 9 of AF. I'm typically regular and last 5 days. The first 5 days of this AF, it was very light and I thought maybe I should take a pregnancy test and I had no AF symptoms. A few hours later on day 5, I started getting typical AF cramps and AF started heavy. The next 4 days were heavy/medium flow. I'm currently waiting for it to stop and wondering what could be the cause of this. Anyone deal with this before?