How Safe Is Taking Lutenyl For Fibroids Causing Heavy Bleeding?

I have been diagnosed with fibroids as csuse of heavy bleeding and put on lutenyl. Problem is the flow seems to be getting heavier (going through pad & tampon in 2 hours or less). Doctor told me to take lutenyl from Day 5 for 20 days. Is that prescription ok? Can I start taking them earlier, like on Day 3. I alteady suffer from iron deficiency and currently on treatment for anaemia caused by heavy flow. Please, advise.