Not sure what is happening here...

Alex • Aspiring personal trainer, and highly active person. Want children in the future, and nanny as a second job.
So I've got the IUD. No abnormal Paps, no STDs (once had chlamydia but that was 5 years and 3 partners ago), no diseases or strange comments on my lady bits. Have tracked my cycles and sexy encounters for 3 years strong. Super health nut, limited processed foods, little to no dairy and soy. Thyroid and blood tests are normal.
After this last period i had light spotting for a good 3 days, not unusual. Happens every few cycles. However its been almost a week now and the spotting has returned. Ive had mild cramps, nausea once a day pretty much the whole week, and today...i cried while we were being sexy. <--- this is suuuuuper abnormal bc i don't cry ever. 
My IUD is in place, i've had it for over a year. i took a test last weekend which was negative....
In your opinions, should i be worried?