Can anyone on this progestrone only pill tell me how it effected your cycles? I went on this at 3 weeks pp. I had a period from the 17/09 till 24/09. Then another very heavy and painful on the 01/10 to the 7/10. Now this morning i have period cramps and back ache. Will it be like this the whole time I'm on it? I take it roughly the same time every day.