I'm 3 days late...

I'm three days late, and what's weird is that I'm on the paragard IUD. I've let my bf cum in me but this is the first incident this has happened, I'm kind of scared.... I haven't tested yet because i feel like I'll end up getting my period.... //// update: I have this really sharp pain on my right side, it's been like this the past couple days, i think it's where my tubes are too... it's so bad it makes me keel over in pain and almost makes me cry. No signs of a period either and cramps aren't a think for me, never have been until I'm actually on my period. I took a test and it was negative.