I had unprotected sex about two weeks ago, I've been having really dark brown discharge with a little bit of blood and bad cramps could I be preganant?

Yes. Yes, you maybe pregnant, if not from this episode of unprotected sex, then from a prior instance. Also, if you've engaged in unprotected sex, then painful discharge could also be due to sexually transmitted diseases/infections. Easy way to determine if pregnant or not is to take home pregnancy test, available w/o prescription at most pharmacies - they're accurate as soon as you're late. Then c doc.