What Could Heavy And Itchy Bleeding With Rashes During Menses Suggest?

Ok, last month I had a super heavy 3 week long period!! My doctor told me I was ok and that my uterine linen was shedding... I still don't know if that's okay. This month I'm having dark brownish/black looking blood... It itches also.. And I even got a little rash. This is embarrassing. What is going on?