How to tell?

How do I know when a herpes outbreak is about to occur? I've only ever had one outbreak from herpes (I've known I've had it for only a few months now) but right now I'm on my period but it's about over. Well whenever I wipe it hurts a little. Maybe not exactly hurt but it feels not right. Also when I'm sitting my vagina just feels different, if that makes sense. Could this be a sign of a herpes outbreak?