Help! Clomid cycle

I took clomid 50mg this cycle cd5-cd9. I started taking opks on cd8 and all have been negative. I just started my period AGAIN today on cd17. Is this normal for clomid to make AF come so quickly again without ovulating? I was cramping sharply on one side but it subsided today. Any thoughts?!?! Could this be something else other than AF? It's too late here to call the Dr.