Unbearable cramps with iud

I'm in so much pain. I have sharp cramps that are coming and going in my pelvic area. I got the iud inserted about a month ago and the past week I've been having cramps that have been trying progressively worse. I thought it was normal but yesterday they got pretty bad and today it's so much worse. My forehead is warm too and I think I have a fever. I usually wait things out before going to the doctor and I don't want to go to the er unless it's necessary because it's expensive. What should I do?