I Am Getting Brown Discharge While On Lutera. Is This Implantation Bleeding ?

Im 27 years old and have always had irregular periods. I have been diagnosed with PCOS. I take Lutera birth control pills in the evening every day. I have been taking them over a year with no problems at all. I have occasionally missed a pill in the past with no probelms. However, I missed a pill about a week ago, but took it the following morning. Also my husband and I have sex several times a week, including when Im taking the placebos at the end of my period. Yesterday, I had bright red bleeding (some in the toilet) but mostly when I wiped. I was shocked because Im only in the end of my second week of white pills. I put a tampon in and when I checked a few hours later there were just two streaks of brown blood on the tampon and the bleeding had stopped. Could I be pregnant? I have recently started a new diet and exercise regimen and have been losing weight. Im also having very light dull cramps. I never experienced anything like this with either of my two children.