Alright, I downloaded Dawnguard DLC then I joined the Dawnguard to fight against the Vampires. Therefore after completing the quest (killing http://www.uesp.net/wiki/Skyrim:Lord_Harkon), I decided to become a vampire so I asked Serana to make me a vampire. After some days in skyrim I decided to cure my vampirism because it makes me look hideous and I am not the magic type of person. Then I join The Companion and they turn me into a Werewolf since then the dawnguard NPC will randomly attack me anytime I go to the Dawnguard fort for side quest.

Note: They stop attacking me after I cured my werewolf (Lycanthropy). Now I have no special powers such as werewolf or vampire, *This Really svcks*

Does anyone know how to fix this? (I don't have any mod)