I am a 17 year old girl who has been on the Yaz birth control for two years now. Since I started the birth control I have had regular periods (only a few days off usually). I recently became sexually active around 3 months ago and the last two periods I have had have been very light, only the brown discharge, very little blood. I have no other symptoms that would suggest I am pregnant, no sickness, weight gain, etc. The only other differences would be a bit of weight loss and loss of appetite in the last 3 weeks. Could I be pregnant?