Pregnant on Mirena/Missed period on Mirena

So I have had the Mirena for 7 months now. My periods were pretty messed up in the beginning months but they are usually always on time, the only irregular thing was how long I was bleeding for. I had unprotected sex for the first time with the IUD a few weeks ago, and now my period is late by 5 days. I took two test when my period was two and three days late and they were both negative. Could this just be my period finally stopping? I also have been very nauseas (vomiting the first few days), sharp pains (but that’s been usual with the IUD), and incredibly exhausted. I have been pregnant before so I know the signs..I just wondering if I should test again or wait it out…I’m just so nervous.