What Causes Nausea, Cramping, Pain, Bloating And Headaches?

I have the mirena iud for 2 years and for the past 2 weeks I have been having nasuea, cramping, sharp pains, bloating, headaches, and my boobs have been hurting and got a little bigger. I went to the dr and she said that my strings are missing, she couldn't see or feel my iud and that my uterus is in the wrong position. I have never heard that before. So, I had an ultrasound yesterday and the tech was unsure of what the iud was supposed to look like and I have been in constant pain since the ultrasound. I feel horrible and am worried about being prego or having something wrong