What Causes Dark Blood Discharge From Vagina?

I have noticed bright blood the last few times I have gone to the bathroom but I can't figure out where it's coming from. I have had many bladder infections in the past so I dont think thats what it is... I have no pain. And my period isnt due until 8 days from now. Ive also looked and cant find anywhere the blood could be coming from... no cuts no period.... idk. Its in the toilet and when I wipe.