Confused?

So I thought I started my period today...I went to the restroom around 1 while and work, wiped and there was some blood on the toilet paper and some blood in the toilet. I was already 2 weeks late so I was like, "okay, not pregnant." So I go on about my day, go to the restroom a couple more times just to be sure I didn't need to change and thing and there was nothing on my feminine products, maybe just a trickle of blood. I get home and there still is just a few spots. So I change and then cook dinner, go visit my family and just got home about an hour ago and I have completely stopped bleeding. I thought I was pregnant at first and went and had a blood test but it says negative. I'm not stressed or anything so I know it's not that. I just don't get what's going on!