Unusual, severe cramping.

I'm in month 3-4 of the Mirena IUD. I had a pretty long couple weeks of just spotting the first month I had it. Now, nothing. This evening I noticed I could not stand up straight. I have such horrible cramping in my lower abdomen and it's been about 4 or 5 hours now. I don't have to poop, no gas, no blood or spotting at all either. Anyone else experience similar? On a side note, my smell has increased ridiculously and my husband worries I'm pregnant. Tests are negative though! I just smell everything!!