What Causes Vaginal Discharges And Bleeding After Starting Birth Control?

hi, i've been having some odd things happening the past 2 days, plus today, im worried about it, and just wanna ask you if its something i should go see a doctor about right away, or if it can wait. about 1 week ago, maybe a little over a week, i had just ended my period, and just 2 days ago, i started having a brown discharge, and it stoped that day, then there was a little bit the next day.. and now today i noticed there was alot of brown discharge, and then after i started having light bleeding. i'm very curious of what it could be, and curious of if its something i should be very concerned about and go see a doctor right away about. and also, i did recently start birth control over a month ago, probably a month and 2 weeks ago, and during the first month of being on my birth control, i did end up having unprotected sex, and was wondering if birth control works within the first month, because my first thought of the brown discharge was that maybe im pregnant. and now im not sure if i should keep taking the pill or not, just incase i am pregnant, because i wouldnt want to harm the baby.