Did I make a big mistake? Terrified 😭

I got my mirena IUD placed on 8/29 and started my period on 9/3. It's come with heavier than spotting bleeding, cramps, and some sharp pains especially during sex. I went to my OB today and she said that I have some inflammation and swollen nodes. She put me on two different antibiotics (metronidazole and azithromycin) for this and said she wants to treat me for adenomyosis. She said if it doesn't get better in 10-14 days to come back. I'm worried now that if I hadn't gotten this IUD then 1. I wouldn't be dealing with this and 2. I am now worried about my fertility for the future. :( We definitely want more kiddos. I'm so scared right now.

Anyone have this happen? Is it due to the IUD?

Did I do something wrong? Anyone else have experience with adenomyosis?

Thanks in advance...