Pregnant?

Kay

So I have a pretty normal cycle 27-29 days. But this month it's been really weird. I was suppose to get my period 8/4 and didn. I started having brown discharge/spotting. I also have had only like 3 cramps which is not normal for me normally I have very heavy cramping. Going on day 4 of a late period Yesterday and today I got some bright red blood. But i mean i dont even think in total since 8/4 i have had enough spotting/discharge to fill a liner. I also have only had very very small blood clots. Like I wouldn't even consider them clots. When I normally get pretty good size ones on my period. I have the copper iud (paragard since 8/2016). Took a pregnancy test yesterday and it can back very negative not even a hint of a second line.