Pregnancy Symptoms...but not pregnant??

Around 5 months ago I got the Skyla IUD inserted and I love her! I never really had any complications or bad side affects other than some cramping here and there etc. I just had my period, and now I'm experienced very sore and swollen breasts, along with bad nausea and I'm very tired. I took a test just to ease my anxiety and of course it came out negative, but I was just wondering, has this happened to any other ladies with Skyla or Mirena? Is there anything I can do for these symptoms?