Opinion please?

I been ttc for 2 years. Nothing. So i stopped trying and had a slip up with a "buddy". A week later i get light pink mucosy discharge for a day. Now i have mucosy cm and its either heavy or none at all. And im getting PMS symtoms and i dont start til 2 weeks? Has this happened to ANY of you girls? I dont wanna say im pregnant. I doubt it.. But a friend was like this during her pregnancy..