I’m scared

Ok so I’m on birth control & ive been on it for almost a year and I usually always use condoms for that extra protection. Sometimes I’ve been bad with taking birth control, like skipping a day or two or not on time, but I always catch up. So last month I was really sexually active and I started becoming really good at taking birth control on the spot. So like 2 weeks into the month I had this random super light bleeding. Why?!? Am I bleeding and it’s not my period yet. Then on my period week I barely bleed. It’s super light and appears a little brown looking on my pad. Guys help me. I’m so scared. I use protection. What is happening... I can’t be pregnant?!?