Hello anon, These are my best thoughts on your situation as one of the gynecologists who is available to help women contacting EmpowHer. I've reviewed the information you sent and the responses of the EmpowHer guides. You are right that the cause of your bleeding needs to be diagnosed before the discussion about treatments.
You and your doctor already know a great deal that's helpful: you have fibroids; you have cycles in which your own progesterone is being produced; you have a past study showing an ovarian cyst; you had a course of treatment with Aygestin and after that went right back to your bleeding pattern. You don't need any more hormonal studies.
Where do you go from here ? Back to your doctor. She can easily do a "transvaginal ultrasound" which will evaluate the lining of your uterus and the potential for the fibroids to be the main cause of the bleeding. The ultrasound might also show a "polyp"-more about that later.
She may (probably?) suggest you have a "D&C". A "D&C" is a surgical procedure involving a scraping of the tissue inside the uterus. Although a D & C is a diagnostic procedure it can also cure the problem. Local anesthesia can be used for the D & C so that you don't have to worry about your anxiety about being put to sleep. A D & C takes about ten minutes. Your doctor might also want to do a "hysteroscopy". That is a procedure in which a special kind of microscope is used to look inside the uterus
and examine what's in there that might be causing your bleeding. The hysteroscopy can be done at the time of the D & C.
Although the bleeding you're experiencing is extremely common, it shouldn't be ignored and a definite diagnosis should be made. No one has mentioned a "polyp"-a kind of overgrowth of a blood vessel in the lining of the uterus, but that could also be causing your problem and could be easily removed at the time of a D & C.
Cancer in the lining of the uterus would be quite rare in a woman with your history. I mention it because prolonged bleeding can be a sign of uterine cancer. That makes it all the more important to get the problem diagnosed and resolved.
I hope this is helpful.