Question...

Af was due last Thursday 11/12. All I've had the past five days is brownish color when wiping, I put a pad on in case and nothing has been on the pad. Took a pregnancy test and it was negative today 11/17. Do any of you have any insight as to what might be going on? Could I be pregnant or is this something weird that just is happening? I have never missed a period before or had this happen so was just curious of your thoughts. Thank you!