Hi ladies! Bleeding after sex?

Hey! Let me give you a lil back story. Last day of my period was the 19th. It was normal up until the last two days. It was very light and scanty. I had sex on the 20th, and have been spotting since then. I say spotting... its pink sometimes a lil bloody when I wipe only. But it started during sex. It was bright red for only a short moment and has been light pink since. Just weird.... anyone experience this or know what it may be? Surely not pregnancy related. :(