You have been cursed by a weretiger. A remove curse cast before the next full moon can remove this curse, otherwise the effect is permanent. It is up to the DM to determine the control you have over the curse.

Tiger form: 40' movement. Cannot speak. Darvision 60'. Passive Perception 15. Strength 17 (Unless your strength is already higher). Resistant to bludgeoning, piercing, and slashing damage from Nonmagical Attacks Not Made With Silvered Weapons.

• Shapechanger. The weretiger can use its action to polymorph into a tiger-humanoid hybrid or into a tiger, or back into its true form, which is humanoid. Its statistics, other than its size, are the same in each form. Any equipment it is wearing or carrying isn't transformed. It reverts to its true form if it dies.
• Keen Hearing and Smell. The weretiger has advantage on Wisdom (Perception) checks that rely on hearing or smell.
• Pounce (Tiger or Hybrid Form Only). If the weretiger moves at least 15 feet straight toward a creature and then hits it with a claw attack on the same turn, that target must succeed on a DC 14 Strength saving throw or be knocked prone. If the target is prone, the weretiger can make one bite attack against it as a bonus action.