A day of spotting

Michelle • Hi I`m Michelle I`m 23 and have been off BC for 2 years now and still nothing yet!
My fertile window was August 29-September 4 (we did have sex 2 times during this time) on September 5th I had just one time of spotting when I wiped then it was gone AF is due September 17th. The passed two days I have felt so sick to my stomach and just not my self. Anyone think there is a chance I could be pregnant?