I need help, I am cofused.

Ashley • Mon, Oct 19

According to this I ovulated on Oct. 1st, I had sex multiple times Oct. 2ed. I had some light spotting on the 4th, 5th and 6th, usually my periods are heavy. My period was due on the 15th, today is the 19th, I took 3 different brands of pregnancy test, all were negative. Could I still be pregnant? How long could it take to receive a positive? Any advice is helpful.