Possibly Pregnant? IUD - TMI

Okay so I’ve have an IUD for about two years now. And there where times that I thought that I was pregnant because I’ve felt nauseous for a couple of days. And every time I took a pregnancy test it comes out negative and then red-ish discharge comes and I believe it to be my period. Since I don’t get many, the IUD stopped my periods. However this time I’m nauseous, having stomach problems and eating the weirdest things for 2 weeks going on 3. And I’m having a copper-brown-ish discharge and I took a pregnancy test last week and it was negative. Could the IUD be preventing an accurate result from the pregnancy test? Or is there something else wrong with me? 🤔