That must be so frustrating for you. Mine was exactly 28 days, after natural mc. All seemed a bit weird (maybe even to normal if you know what I mean) to me but then 2 days in to mine I was on the verge of phoning NHS 24, sorry if this is TMI but I was having blood clots the size of small grapes, and the blood was really red like proper blood, spoke to my midwife friend and she said some people can change etc. I have just never had an AF like that was a bit freaked. Completely stopped now so number of days wise seems normal.