I found the test they did first more than the actual insertion of the mirena. I almost chickened out as they said the mirena itself is worse. I had my period at the time of insertion, so cant comment on bleeding.

I felt a bit bad that afternoon, some pain an nausea. A couple of days later, I was in a lot of pain, felt faint and very ill. It felt like one of my ovaries was trying to force its way out the back of pelvis. I was very close to getting it removed at the ED that night, but then it all settled down.

Had a bit of minor bleeding/spotting for a couple of months, then nothing for 6 months, then a 3 week period (spotting, some clots), now nothing. When I got the 3 week period I had extreme tiredness before onset and pain in my pelvis as I had after it was inserted. So atleast I now know if I feel that that pain with tired to expect a period.

Saying all that overall I am happy with it. I was having a 6 day period every 23 days, with heavy bleeding and extreme tiredness. So no period for months with the odd long one really is an improvement.