I felt like you about the Mirena/IUD. Was never going to get one.
Then started having random periods and flooding (peri menopause), went to GP after I bled through to my clothing in work. GP advised Mirena, and I decided to try it as I was getting so paranoid about leaving the house.
I know some people have a difficult time having it inserted, and I'm not going to say it was pain free, but the GP who did it has done loads, knew what she was doing and it was ok and over quickly. Then I went home, took it easy - hot pad, painkillers, had quite uncomfortable cramping for two days, but not enough to stop me going to work or anything.
Flooding stopped straight away. Periods were still a bit random, but next to nothing of them, and by the time I had a new Mirena fitted this year, they were just a day or two of spotting. Changing to a new one was straightforward and less painful than the first one.
The only weird thing is period pain, when I get it, is more on the left now, but that's probably to do with the fact I had my right ovary removed.