Could I be having a miscarriage?

August 22-28, I had my period and two days following there was no blood. September 2, I had little spotting and it hasn't stopped since. I am now getting nervous because I'm starting to bleed a little more. At first it was a light red now it's almost brown. It doesn't hurt only some cramps here and there. I have tried using a pad and maybe one or two drops showed and it doesn't fill a tampon. I have been trying to get pregnant for about a year now and had gotten off the pill about a year and a half ago. It doesn't hurt to have sex.