Once a normal person, you were attacked or were willingly bit by a vampire thus turning you into one yourself.

Ability Scores: Strength, Dexterity, Intelligence or Charisma

Resistance: You are resistant to Necrotic Damage

Feat: Shadow-Touched

Blood Thrust: You crave blood and must drink it once per day to avoid becoming Blood Starved . You gain the Bite action (Once per Long Rest) and bite a willing, grappled or incapacitated creature. Roll an unarmed strike to see if you hit and to calculate how much damage is dealt. If you successfully bite into a creature, you suck their blood regaining half the damage dealt. If you are at full hp, you gain that health as temporary hp. 

Blood Starved: If you do not drink blood at least once a day, you become Blood Starved. When you are Blood Starved, your maximum hp is lowered by double your constitution modifier for a minimum of 8 hp. Additionally, you -1d4 to any damage you deal. 

Sunlight: If exposed to direct sunlight, you take 1d8 fire damage every 6 seconds (1 turn).

Languages: Common, Vampiric

Skill Proficiencies: Survival and/or Stealth and/or Sleight of Hand and/or Deception

Tool Proficiencies: Thieves’ Tools

Equipment: Choose A or B: (A) 2 Daggers, Thieves’ Tools, Crowbar, 2 Pouches, Traveler’s Clothes, 16 GP; or (B) 50 GP