What is this?

Hey I started my period on the 4th of this month and lasted 4 days. It seemed like a normal period quite heavy just abit shorter than it normally is. I came off on the 8th and had unprotected sex on the 15th. I think it might have been abit early to ovulate? But I’m not sure. It’s the 24th and I’ve started bleeding a light pink with discharge and I’m confused what this could be? Could it be spotting or is it too early as it’s only 9 days after sex and I’m not meant to start my period yet?