I have been on my menstrual cycle now for 3wks?

I’m 39yrs old and have 4 children. I have been on my menstrual cycle now for 3wks. It has stayed at a consistent heavy flow the entire time. I’m wearing super tampons and having to change them at least 6 times or more a day. It doesn’t seem to be slowing at all. My normal cycle is 5 to 7 days with the 1st 3 very heavy and then slowing dramatically the last 3. I’m starting to worry. What can I be?

Age: 39yrs
Female
Medications: None