I'm sorry you have had some bad experiences. I know women who have had bad symptoms from Mirena also. I too know women who love Mirena. Everyone is different. I personally (always was a pill girl) had to switch birth control pills three times before I found one that worked for me and didn't give breakthrough bleeding or mood swings. It's odd you had irregularity on the pill. It's supposed to regulate your cycle. Were you skipping cycles? Is that what you mean? Have you tried the pill since delivering your children? I know it can be annoying trying to find a method that's right for you.
Regardless, I'm sure you know about birth control, but for what it's worth, here is an article highlighting birth control choices that may give you some more options: Which Birth Control is Most Effective?
Good luck and let us know how you're doing in the future.