What Causes Vaginal Spotting Along With Mild Cramps While On Petogen?

I was diagnosed with anemia and my doctor put me on ginette but after using it for 2 months I noticed that my flow was longer and still heavy, he put me on petogen on 13 -03 -2015 and up to date I am still spotting dark brown heavy with mild cramps and pains in my ovaries, what can I do,please help,thanx