What Causes Pain And Heavy Bleeding Having Diagnosed With Fibroids?

hi im 37 years old ive just been diagnosed with fibroids my gynacologist has put me on norethisterone to delay and calm my menstrual periods started taking them from day 1 of my period and is still menstrating yesterday tea-time i started suffering with exscrusiating pain and heavy bleeding and still in pain this morning please can you help and give me some advice