Mirena Symptoms or Pregnancy?

About a month ago, my breasts increased an entire bra size and have been sore to the touch ever since. My appetite has increased like crazy recently, and I'm getting crazy heartburn. I'm also super emotional even when I try not to be (it's driving my bf crazy), and I'm always so tired. Last period was in December, then I had a little spotting mid January, but it was just old blood. I got the mirena inserted in July last year, and haven't had these symptoms until now. I tested in mid January, and it was negative, but idk if over the counter tests can read for someone who has this kind of IUD. Suggestions? Yes we do have unprotected sex.