Well, my suggestion to you is, if you don't get a period on the mini pill, don't freak out cause it's known to happen. If you do have a period regularly like I did, don't freak out either cause it doesn't mean anything different. Some women are totally lucky and don't get a period and others are not so lucky and keep getting it. It is still working either way so don't freak out.
I loved the mirena just until the last year. I was having really bad cramping I had to get it removed.
I still got a period while on the mini pill. A lot of women don't have a period. But I assume it's because a lot of women start it while breast feeding, which delays a woman's period after childbirth anyway. I've never been pregnant so I don't know if that's why I still got my period anyway.
In any case, you have to take it every day at the same time for it to be effective. And if you miss any, it has a higher fail rate then the regular pill. Also, you keep taking it through your period. You take it every day regardless of anything.
I did the opposite of you. I used to be on mini pill and changed to Mirena. Mostly cause I didn't want periods anymore and it worked, just some spotting during when I expect my period. It beats having to carry an entire suitcase full if pads and extra clothes everywhere due to my period!