What Is The Heavy And Prolonged Bleeding After A Blood Transfusion?

I have been through 2 blood transfusions (severe anemia), and my last one was just a month ago. Since the last transfusion I have had my cycle twice.... both times I have felt very weak, tired, and even nausea'd. My flow is heavier than ever and lasts longer. This is very abnormal for me, but no one seems to listen. What should I do?