What Causes Pink/brown Vaginal Discharge After Having Unprotected Sex?

hi i had my period 2 weeks ago,and just the other night i had unprotected sex as me and my husband are tryingg for another baby..just 2 days later i had light pinkesh bleeding ,but it only lasted for 10 minutes and then there was no sign of it ...its the second day now and its a really light brown colour...i cant tell if its my period because it stops completly and i only get a show when i urinate...the same thing happend 2 mounths ago but i then ended up with staring my periodplease please help me i am really worrid....the same thing happend 2 mounths ago but i then ended up with staring my period