What Causes Spotting Along With Mild Stomach Cramps?

I am 4 days late, I started spotting yesterday but only when i wipe after using the bathroom and its dark brown. I have mild cramping but that is it, is there a chance i could be pregnant my husband and I have been trying for 2 years and its always a let down to get excited but i wanted to ask first. I have normal periods usually 28-29 day cycle i usually start around the day it says on my app and i have never been 4 days late