Plan B and BC

I am on my first Month of birth control (combination pill), and during the first 7 days, I took one of the pills later in the day, I usually take it at 7am, this was at 3 pm, I had sex that night unprotected, but then took Plan B the next day, I had unprotected sex on day 8 of taking the pill, but he didn't cum at all. I had sex unprotected a few times throughout the month, and cam inside me once a little bit, on day 16, on day 24 I started to have light bleeding that turned to heavy the next day, and then the day after that it was light, and at night a little heavier, then for another 4 days it was light, and brown, now I am scared I am pregnant, am I? Or just had a weird period? I am on the 21 day pill, so I am not taking a pill until this Sunday, PLEASE HELP ME! I'm going crazy