When Will Prostrap SR Injection Start Acting To Control Vaginal Bleeding?

I have a fibroid on the inside of my womb about 4.5cm. It has caused me to bleed non stop (flooding) non of the blood stopping tablets like Northistrone/Transamic acid... are working. I was given a Prostrap SR injection 2 days ago and told to try taking Transanmic acid tab again until I see my surgeon. I was given a blood transfusion yesterday as I am bleeding so much. Can you tell me when the effects of Prostrap start having an impact - and when this bleeding is expected to stop. (I am 33 and have had no children).