I Had Unprotected Sex On August 21st Which I Didn't

I had unprotected sex on August 21st which I didn't know was my ovulation day according to my period tracker. I've been having mild cramping in my abdomen and yesterday when I wiped there was a very light pink color on the tissue. However I haven't seen it since yesterday it happened only once. I took two pregnancy test and they came out negative. I am suppose to get my period next week but I wanted to know is there a chance I could be pregnant?