Just after any advice..

I am now cd33 (usual cycle is between 27 to 30 days). I have consistently had creamy cm and cramps up until today where I am having slightly brown cm but I only noticed this when checking my cm internally. I have done multiple pregnancy tests and all bfn! I don't know when I should make a doctors app as usually you have to wait until you are 5 days or more late. Have any of you had a similar experience to this? I'm very confused!