Brown discharge is it implantation?

My boyfriend and I had sex and he came inside when I'm suppose to ovulate but I'm on the pill. I was suppose to ovulate on Jan 4th and I'm having some brown discharge today on the 11th. I don't think it's the start of my period because it shouldnt come for another 10 days. I accidently missed one of my pills about a day before. I'm randomly bleeding a little and I've been feeling nauseous I'm worried :(