Uterus contracts symptoms and conditions

Aged 40 and with an 8 year old son, I had Mirena coil fit on 1st August after having the depo injection for almost 2 years and being fed up about my weight gain. I was advised by doc that there was no weight gain with Mirena as the hormone was local rather than in your blood system. I was in absolute agony around half an hour afterwards. It felt like I was having contractions every 3 minutes. Rang doctor and was told to take Ibuprofen along with Paracetamol, which I did. The cramps didn't subside until around 5 hours later. I was in tears with the pain. I suffered for around a week after with period pains. All seemed ok after, other than I checked and couldn't feel the strings. I also asked my partner to check and he couldn't feel them......I went last week for my four week check and neither could the nurse! I am now going to have a scan on Wed 10th Sept to see where it is! Can anyone tell me what happens after this....if they find it what will they do?