I felt fine getting mine removed. Started my period a week or so later. No problems. I'm currently on my 2nd one.

I didn't have a Mirena, but a diff kind I bled for two weeks straight. Passed large amounts of clots. It's just your body going back to normal. Just be aware if you do get it removed. I bled so much I had to wear a tampon and pad and had to change very often. It's not bad when they take it out it doesn't hurt or anything like that.