Advice

Hey there! I had unprotected intercourse during my fertile window and I was supposed to start my period on Monday (October 5th)... Saturday the 3rd I started having some brown spotting, this usually happens for about a day and then the next day I will start my actual period, I have had the brown spotting for 3 days now, but no blood.. I have taken 3 pregnancy tests and they have all been negative. Could I still be pregnant? My friends don’t think I could be pregnant and think all the stress I have had lately could be affecting my period. Any advice?