Alot of women have had what they thought were positive experiences for a while on Mirena until things took a turn for the worst. It sounds like you are pondering...I have a VERY strong/healthy body...I have birthed 4 children and I am NOT sensitive to birth control and other things...meaning I do not usually have side effects from things.The Mirena literally made me feel like an 80 year old woman. I had muscle/joint pain (Sound weird?...It is)Extremely tired...moreso than when preggo...gained 10 lbs...felt and looked 5-6 mos. preggo...lost sex drive quite a bit...headaches every day...felt like a loser...and I could not focus clearly,very forgetful....basically I felt very handicapped and sloooooow. The strings also drew up into my uterus...so I had to have an operation to remove it. Please research this site...the Mirena is HORRIBLE...I only had mine for 2.5 months and it did all that to me in that short time. Once it was out all the side effects dissapeared. The longer you keep it in...the longer it takes for your body to get back to normal.
And I had it way easier than ALOT of women...PLEASE don't get it.Best of luck.