What Causes Heavy Periods And Pressure In Uterus?

Nine months ago I was raped. The first 3 months I did not have my period still hadn't checked if I could be pregnant. The fourth month it came in very lightly but a brownish color not really blood at all, and it remained like that till today. Now I'm having a pressure in my uterus. I thought everything was fine cause this whole week I've had my menstrual normally. Now The pressure is beginning to worsen & I'm bleeding more. What can this be?