Pregnant while using IUD Skyla

CA

My first baby was born just 5 months ago and I had Skyla IUD put in at my 6 week PP check up. We followed all the rules and used condoms the first 2 weeks and everything was going fine. Just last week I started having horrible migraines and lower back pain, nausea, decreased appetite, extreme fatigue, and swelling I'm my legs and feet. All early symptoms I had when I was first pregnant. I took a pregnancy test but it was negative, my next period isnt due for over 14 days though. So it could be really early🤷‍♀️ Kind of freaking out... anyone else experience this?