Kyleena IUD

This is going to be kind of long but I got the Kyleena IUD inserted at the end of October 2017, 2 months after I had my son. A month later I got it checked to make sure it was still in the same spot as you’re supposed to. I now check it every month to make sure I can still feel my strings. My last period was January 26th & my fiancé and I had sex on February 9th & 10th. He travels a lot for work so that’s been the last and only time since my last period which would’ve been when I was ovulating too. I’m 4 days late for my period, have been have a lot more creamy watery discharge (which I remember from when I got pregnant with my son) and I have been a lot more tired than usual. Occasionally I get this twinge feeling in my lower left abdomen, although it isn’t painful, it just kinda feels like tightening. When I checked my strings today, I only felt one. I took a pregnancy test three days ago, and I thought it was negative but now looking at the picture I’m wondering if there’s a very very very faint line and maybe I should test again. I’m freaking out because I’m thinking it could be ectopic because of the IUD but also I’m in no pain? And I’m also not trying to jump to any conclusions because I know birth control can alter your body in a lot of ways but I just wondered if anyone had a similar experience with an IUD and they weren’t actually pregnant. 😶