Confused?

My period was due the 18th. I woke up around 2am and had just “started.” It was super faint spotting. Then turned to a darker color but still pretty much only when wiping. The whole time I was on my “period” it only ended up being maybe a quarter size on a pad. I only had sex on February 14th. My “ovulation window” was the 1st and so on. Is it possible to still be pregnant?