I'm currently on the mirena Iud and I have been for 3 years and only within the last year My hormones have been everywhere. I went to the doctors and they've put me on loestrin 20 aswell.. Which has helped a lot! The only thing is.. How am I supposed to know my cycle when I've got an Iud and the pill? Most of my periods are quite light and last a couple of days.. But I'm never too sure when I'm going to come on my period?