Implantation bleeding is usually a very light pink or a small amount of red blood. When I have had it it only happened once and if I wasn't looking for it I would of missed it. Brown is a sign of old blood.
It could be! but there is so much that comes out of us women theres not telling. I had somewhat the same issue. Read my question and maybe in the next few days when your cycle is due if you don't miss it you can relate . Its under "i could be further than i think " i posted it sometimes yesterday so itll be on the f1st 2nd or 3rd page. After your cycle is due i would take a pregnancy test. Good luck darling.