Missed period?

Kaye

Hey guys so my period is 5 days late, it was suppose to start on last Saturday and as of right now there is still no sign of blood. It is now Wednesday and its literally the last day of my supposedly cycle. I usually never have any late periods it always comes on time. I have a feeling I am pregnant because me and my bf have unprotected sex and on the 28th of September I had brownish pink discharge possibly implantation bleeding. So I plan on taking a pregnancy test but I don't know when to take it because I took one yesterday on Tuesday and it came back negative so I'm guessing its just too early. I think maybe this Saturday morning I should take it but I have a feeling that's too early. Any suggestions on when I should take it?