What Causes Spotting A Week Before The Menstruation?

Hi,

I am 30yrs old, Weight 120lbs. I have regular periods. My period is due in 5 days. But i got light pinkish blood(vaginal) when used the bathroom yesterday, and none since. Spotting is not normal for me so I am a bit confused and worried. I did have unprotected sex 6 days before.



Please advise