Ladies help ease my mind!!

About a week ago, my boyfriend and I had sex (using a condom.) however, we weren’t sure if it broke or not so I took a Plan B about an hour later. I’m not on birth control either, and this was my 3rd time taking Plan B. Two days ago, I started bleeding. It started out really light and a brownish color, and now it’s heavier and looks like a normal period. I’m concerned because I don’t know if it’s the pill making me start my period early, or if it’s implantation bleeding. I’ve never had an early or late period before from Plan B, I’m super confused! Has any one else experienced this?