Mirena and pregnancy?!

I’ve had the Mirena IUD a little over a year. For the last couple weeks I’ve been experiencing some abnormal (for me) symptoms.

1. Dizziness

2. Nausea and occasional vomiting

3. Fundal pressure (below my breasts going across)

4. Heavy fatigue

Has anyone gotten pregnant on the IUD? Or am I overreacting and reading too much into these symptoms?