Suggest Treatment For Consistent Vaginal Bleeding

I'm 30 years old, 5'2'' and weigh 9st 3lbs. I've had an ongoing gynae problem for almost two years now where I have continued to bleed consistently with no regularity for all of that time. The bleeding varies between heavy and having to wear and change sanitary towels every four hours to just a mild spotting or pinky discharge. The longest I have gone with no bleeding at all is 3-4 weeks in those two years and that was just the once. I had a mirena coil fitted in September, but have continued to bleed. After examinations I was diagnosed with having an ectropian(?)/cervical erosion. Last week (Tuesday 17th May) I had it cauterized and was fine with no symptoms afterwards. But now 9 days after the procedure I've started to bleed, (a funny sort of pinky blood with bits in!) and am experiencing a nasty fishy sort of smell from the vagina, which I've never had before. Even after washing it's immediately there again. Please can you give me some advice as to what may be causing this and if you feel I should get it checked out again. Thank you