I could almost gave written your post a yesr ago. I kept going back to my GP telling her about how heavily I was bleeding. I tried the Mirena, Tranexsmic Acid, Norethisterine, and Ibuprofen. Nothing worked, I was having to change Ultra tampons every half hour, wearing maternity pads, and experiencing periods that lasted 16 or 17days every month.
I eventually kept a very detailed diary if my period one month (approx amount of blood, protection used etc) and took it to a different GP who immediately referred me to a gynae consultant.
I had 2 hysteroscopies, and a scan, which showed a large fibroid in my womb. Had it removed, periods are now 3 days long, really light and I feel do much better.
It also turned out that I was anaemic from the blood loss, and that has now been sorted, so I have lots more energy.
Please do go and see a different GP.