Currently I'm on a one month cycle birth control that I take every day. I haven't missed a pill this month. Last week and two days ago my fiancé and I had unprotected sex where he finished in me. Now I'm having some dark brown spotting that is thick and like mucus along with some cramps and mood swings. After doing some research online it goes from I can be pregnant and it's implantion bleeding to I could be ovulating. Has this ever happened to anyone?