I have a copper IUD and me and my partner have unprotected sex all the time. I haven't been worried about pregnancy for a long time because of the IUD but right now I'm freaking out.

I'm 16 DPO or so (I don't really keep track anymore), my period is technically a few days late, yesterday my nipples started BURNING- they felt like they were on fire. Today my nipples feel thick and bumpy and they feel foreign to my body plus they're still really tender. I've been cramping for several days (pretty normal), today the cramps got worse and I started to bleed a little, naturally I thought my period started! But now, several hours later, there is no more blood and the amount that I bled wasn't even enough to stain my underwear. On top of this, I am an emotional mess, I'm having crazy dreams and I am so, so exhausted.

It sounds like I'm pregnant. I feel like I'm pregnant. I took a test today and it was very clearly negative (it was one of those $0.89 at Walmart though, not sure how accurate those are)... What do I do now? Is anyone else in the same boat? Has anyone else had this happen? How do I go about a potential pregnancy with an IUD in? I need some encouragement.

PS: I'm still cramping A LOT, but no bleeding. Is this normal for early pregnancy? Or since I'm cramping should I expect my period to show up??