I have been on Yasmin pill for around 3 year now. Although I have been prescribed the antibiotic flucloxacillin and been taking it for 4 days now (7 in total) I have experienced very slight bleeding. And had unprotected sex last night, Could I be pregnant? I have double backed my pill ( I am going away today) so I'm not sure if the bleeding is for that reason? Or the antibiotic has stopped my pill from working? If so, should I stop taking my pill or wait until I have finished the pack just incase i am not?