Am I preg!?

Ok so I had Brown stretchy discharge on Oct 6th- through the 11th..never filled a liner..only would show up once or twice throughout the day. I was supposed to start my period on the 14th of oct..never did. When I took pregnancy test they all came back -, so I gave up. But about Sunday my nipples were sore and now are very but when I took a pregnancy test it was a -. & it's been a good 3wks since the Brown discharge..so can I be pregnant??