My Girlfriend And I Had Sex Yesterday....after The Sex She

My girlfriend and I had sex yesterday....after the sex she noticed a bloodstain while peeing...
We didn't pay much attention to it....but this morning it happened again.....and the color of the discharge from her vagina has now changed to reddish-brown.....she is not on her periods....they come around 24th of every month....also she had taken a contraception pill last week....