Help?

Well, I'm just curious! My period is 4 days late, no signs or anything but I took a pregnancy test yesterday afternoon and there was nothing. My periods are always on time, and the last time I went to pee, I saw small spots of brown on the tissue, but not in my panties, as well as the smallest spot of like, a very light pink on tissue that morning. I'm not sure and this is probably worded weird and confusing, but I'm just wondering. Any help is greatly appreciated! 😊