Hi I Have Had My Period For Over Two Weeks

Hi I have had my period for over two weeks now and am changing my tampon every half hour. The dr put me on tranexamic acid...but it didn't stop any bleeding. They put me on primulot now....I have taken it for 4 days and am back to heavy bleeding. I have had blood tests and pelvic ultrasounds taken....which have shown nothing. I'm not sure what to do next?