You could really take a test now. Once you are late if it is going to be positive it will most likely show up now. If it comes back negative, I would wait a couple of days and maybe take another test if that is negative too and you still haven't started then I would go ahead and make an appt. That way if there is something wrong they can get in there and take care of whatever needs to be taken care of. :) hope that helps! Wish you luck, hope it positive for you!