Pregnant? False?

Just wondering whats going on haha,

So on about Sep 18/19 I did have sex wih my partner. During the end of the month/beginning is always the 1st day of my period. I have a 29 day cycle; my last period was Aug 31. I havent gotten my period, usually its very heavy. Today, when I wiped myself I noticed very light brown blood and every time I used the bathroom it would be the same. However, instead of getting heavier its getting lighter. I haven't had major symptoms only a tummy ache here and there but the norm and my boobs a little tender. Any suggestions? Have you had a period that was a light brownish color and mistaken for something else? Should I take a test or wait longer?