See a Chapel Healer
First, it should be made sure that you understand the difference between Vampirism and the disease called "Porphyric Hemophilia" (aka Vampires disease). If you suffer from actual Vampirism, you will have all the common traits of the vampire (boosted stats, pale skin, weakness to fire, etc). To get rid of this, you will have to complete the quest "Vampire Cure". However, if you have just been bitten by a vampire less than three days ago, and haven't rested since, you will only have Porphyric Hemophilia (pre-Vampirism, if you will). Porphyric Hemophilia does not give you ANY of the traits an actual vampire has, and can be cured just like any other disease (see a Healer, pray at an altar, take a Cure Disease potion, etc etc).
Hope I helped!