Sua suposição não está correta, somente o dano que sobrou do ataque é transferido para a sua saúde humanóide. (Pense no Wild Shape como um tipo de "overshield" ou "bonus health")
Ex:
You have 12 HP in your beast form. The barbarian that you are fighting hits you dealing 15 points of damage. This leaves 3 HP left over. So that remaining 3HP is dealt to your character's health pool.
Aqui está um exemplo do RAW
When you transform, you assume the beasts hit points and Hit Dice. When you revert to your normal form, you return to the number of hit points you had before you transformed. However, if you revert as a result of dropping to 0 hit points, any excess damage carries over to your normal form. For example, if you take 10 damage in animal form and only have 1 hit point left, you revert [to normal shape] and take 9 damage. As long as the excess damage doesn't reduce your normal form to 0 hit points, you aren't knocked unconscious.