I downloaded Hearthfire for my xbox skyrim and I earned enough money to buy a house in Morthal and I was already Thane but there was no option to buy then while I was doing some quests I had to kill Vampires and I realised my character got turned into a Vampire at some point. So it seems I have Dawnguard Rather than Hearthfire. Can anyone help me?

P.S. I just downloaded a new copy from Xbox marketplace because my disk broke.