Hi , goodness, I'm sorry you are experiencing awful cramps and back pain. Sending so many gentle hugs your way right now. We aren't medical professionals and unfortunately cannot give medical advice but I can speak to my own personal experience with an IUD. I got a low hormone IUD at the beginning of March for moderate cramping, hormonal mood swings, and heavy irregular periods that I was experiencing for a while. The first month and a half for me personally, were pretty painful (cramping, really quick short stabbing pains in my uterus especially if I moved while seated too quickly, and just felt super tender and achey all around my abdomen and uterus) and have since gotten milder and milder. I also experienced super irregular, however definitely lighter, periods during those first few weeks. I have started experiencing some lower back pain which I never really had before this IUD and it seems to come and go when my cycle would typically start. That has just been my personal experience with it but honestly, and I know everyone says this but it is true, everyone's body is so different and reacts so differently to medications. I wanted to leave some articles here for you to check out if you'd like (seriously no pressure - there are quite a few because I wanted to address a few things you mentioned above) while we wait for others in the community to chime in with their experiences.
https://endometriosis.net/clinical/iud
https://endometriosis.net/symptoms/leg-pain
https://endometriosis.net/symptoms/fatigue
https://endometriosis.net/diagnosis
I so wish I could give you a big hug right now . Please know that you have a whole community of support here for you whenever you need it. I'll be thinking of you!! 💛 Kayleigh, Endometriosis.net team