I'm ttc and have a 28 day cycle i ov on 11/29 and was supposed to get my period today instead got little blood bright red and dark what does it mean?

Period: If you started bleeding on the day you were supposed to have your cycle then it sounds like this is your period although just a light one. If you are thinking you might be pregnancy simply check a pregnancy test.

Blood: It most likely means your period is going to start. Given the timing this is not 'implantation' spotting. Are you sure that your ovulation was twelve days ago in a 28 day cycle? Ovulation usually occurs just shy of half way through a cycle and the fertility days are the five days just prior to ovulation.