Bleeding disorder?

Mi
Ok so, long story, pop your popcorn and grab your coke. Since I started my period at 11 I have had the worst cycles. I go anywhere from 5-70+ days and I go through almost a full box of tampons a day. I went to the emergency room in 2012 for it and my hemoglobin was at 8.2 and dropped to 7 in an hour. They did an emergency blood transfusion and kept me for 4 days. My hemoglobin got higher, I started feeling better, and they released me. I've been through about 4 gynecologists and none of them have been able to find out what's wrong with me. The one I'm currently with has come to the conclusion that it's a bleeding disorder but she doesn't know which one. She knows there's only about 300 cases per year across the US. They've tested me for endometriosis, PCOS, Von Willebrand. They know it's something to do with my platelets. I'm just wondering if anyone else experiences something like this? If so have you been diagnosed with anything? They have me on 40 mg of provera a day and I'm still bleeding through it. I'm so tired of being restricted of everything in life. I want this all to be over with. I know they're the doctors and they should handle it but it's been 4 years and I'm ready to scream 😡