Hi My Girlfriend And I Had Sex After The Last

Hi my girlfriend and I had sex after the last day off her period she took norlevo in less than 24 hours after about 4 days she started bleeding and on the second day of the bleeding the bleeding became darker now it's been 4 days with the bleeding the bleeding became lighter is this something normal and what are the normal precautions to be taken because I am a bit worried about this issue please I need a fast response thank you