What Causes Heavy Bleeding With Clots During Menstruation?

Hi, may I answer your health queries right now ? Please type your query here...I got a Cortisone shot 2 and 1/2 weeks ago and at first I had a browish blood like an old period, now I am having heavy bleeding with clots. I am not due for my period for another 2 weeks, is this normal. Also a lot of cramping