Severe breast pain after 5 years on mirena

Hi... I was hoping someone could help... I have had my mirena for almost 6 years ( next month ). Planned parenthood told me at 5 years when I went to get a new one that it was extended for another year. So I left it in. So about 2 months ago, I started getting sore breasts. Then I realized they seemed bigger. I immediately thought I was pregnant. I went to planned parenthood and they said no I'm not pregnant, and nothing's wrong. After a few more weeks, the pain in my breasts has been severe, to the point of me waking up in pain. They are definitely larger. So I made an apt with a private obgyn. She told me the mirena is definitely NOT approved past 5 years and so now i actually have an apt tomorrow to get it replaced. She said she's not sure why my breasts hurt as bad as they do so I had an ultrasound just in case which showed nothing. Anyway, my question is, is this a normal thing to have severe breast pain after almost 6 years? Could it be that it's stopped working and my hormones are going nuts? I asked this question to the Dr and she really had not a satisfactory answer... Except to say that let's see what happens when you get the new one in. So I have been really freaking out cuz this is not normal tender breasts, it's awful pain. But I don't know what else it could be so I'm wondering if any one else has had anything like this happen?? Sorry for the rant but thanks!!