Help!!

Im A week and 2 days away from getting my period and I had sex yesterday and I checked after and I wasn't bleeding but then about 5 hours later I bled a little bright red and so I wiped it off and went on my way then today I went to the bathroom and there was blood in my underwear dark brown! He didn't cum in me we used protection and pulled out! I don't know what this could be! Any ideas?