I am four days late for my period, and today on the fourth day I have a light brown discharge when I use the bathroom and I wipe. My periods are always right on time, I have had no blood. Me and my husband are trying to have a baby, and we do not use protection of any kind. I am 24, I took a home pregnancy test and it was negative. I have been really tired lately, light cramping, and my lower back is killing me, and my smell senses are very highten. Could I be pregnant?