Why have I got brown discharge and blood when I am not due on my period could I be pregnant?

Hiya am sexually active I had my last period over a week ago now but I've been having brown discharge and bit off blood from my vagina for the past two days its only a small amount but I had sex the day I came off my period, what could this mean?

It could be normal. Sometimes, there's cervical bleeding after sex... especially if things get a little rough. It's not a big deal as long as you're otherwise healthy.

Here's a closer look at what's going on in there...
http://www.beautifulcervix.com/cervix-photo-galleries/photos-of-cervix/

Also, Planned Parenthood has a chat line (phone, online, and text) where you can ask women's health questions for free. The medical professionals who staff that are far more qualified to answer than any of us.
http://www.plannedparenthoodchat.org/