i went through a stage where i was having irregular menses (spotting) for weeks. i found out i have a small cyst on my ovary.
then i started bleeding very heavy just like you. the doctor took a lot of tests to see if i have fibroid tumors, cancer, a low grade infection, etc.
i didnt have anything so i was told i have dysfunctional uterine bleeing.
i read this can be caused my high blood pressure which i was recently been diagnosed with. i also gained a lot of weight in a short amount of time.
i had a hysteroscope (camera in uterus) and d&c (scraping of the lining or uterus. since i wasnt getting a regular menses the lining of my uterus thickened, so they scraped it.
birth control pills regulated my period. it took the doctor a whole year to help me.
i'll private message you some information and i hope it helps.