What Causes Dark Red Blood During Periods?

Hi my period came a week early and ive been bleeding dark red blood for the past two in a half days then on the 3rd day the dark blood only comes when I wipe like I'm only spotting which is very unusual for me my period only lasts for three days then its done I never spot after the blood has stopped I'm also very sexually active I've also took a bath during this time and have seen one small little pink tinged blood come out of me the day I started this week early period was 14 days exactly after conception and the this whole so called period was dark red and brown never had bright red what do you think is wrong with me ? Maybe pregnancy ?