Pregnant with Mirena IUD?

Hello everyone,

I've had the Mirena for a little over two years and I love it. I still get regular periods but they're super light. A few days ago I woke up with my boobs being very painful and I felt like they're bigger too. I asked my boyfriend if he noticed that and he said that they seem a bit bigger too. Yesterday I was also feeling pretty nauseous and had some odd cramps so we got some pregnancy tests. The test was negative yesterday, and negative again today but my boobs still feel painful, I'm nauseous, and super exhausted. I'm not supposed to get my period until next week and I know it's difficult to get a positive test until a couple of days before the expected period but I would want to know sooner since the IUD is still in me and if I am pregnant I would want the baby to have the best chance of survival. Any tips?

Edit: I should mention that on the first test I thought I saw a very faint line but I'm not too sure.