Creating Enemy health

Unity Engine
1

I am trying to implement an enemy health system where it takes more than one shot to kill an enemy. I’m doing a simple test and trying to do a simple two shots to kill for now but after many bullet shots at the enemy, the enemy is still active. What am I doing wrong?

using UnityEngine;
using System.Collections;

public class EnemyScript : MonoBehaviour
{
    private Rigidbody2D enemyRigidbody;
    public int health = 100;
    private int direction;
    public Transform target;
    public float speed = 1f;
    Vector3 targetDirection;

    // Use this for initialization
    void Start()
    {
        enemyRigidbody = GetComponent<Rigidbody2D>();
    }

    // Update is called once per frame
    void Update()
    {
        enemyRigidbody.freezeRotation = true;
       
        targetDirection = target.position - transform.position;

        transform.position += targetDirection * speed * Time.deltaTime;

        if (this.gameObject.name == "Bullet")
            this.enemyHit(50);

        if(health <= 0f)
            this.gameObject.SetActive(false);
    }
    void enemyHit(int damage)
    {
        health -= damage;
    }

  
}
2 
if (this.gameObject.name == "Bullet")
            this.enemyHit(50);

erm what? if your enemy is named bullet it hurts itselft? doesn’t seem to make sense.
I would say your problem is that you never call enemyHit.