Bleeding for 9 Weeks 😩

Hi I gave birth on the 2nd of January and started my first period on the 16th of April and it hasn’t stopped. I’ve been bleeding non stop for 9 weeks with small clots like a proper period I’ve been back to the doctors 3 times and they are saying it’s normal and have checked for infections but they were all negative and now they won’t do anything else. Has anyone had a similar experience and what tests did you have? It seems I have to ask my doctor to do a particular test for something before they actually will :/ (this has never happened to me before my periods were always regular and lasted 5 days)