Unity 2D bullet bounce

I am trying to make a 2d top down shooting game, but instead of the bullet disappearing when it hit the wall i want it to bounce off of the wall. Then when it hits the enemy to do damage and disappear.

This is my health code:

 using UnityEngine;
 using System.Collections;
 
 public class DamageHandler : MonoBehaviour {
 
     public int health = 1;
 
     public float invulnPeriod = 0;
     float invulnTimer = 0;
     int correctLayer;
 
     SpriteRenderer spriteRend;
 
     void Start() {
         correctLayer = gameObject.layer;
 
         // NOTE!  This only get the renderer on the parent object.
         // In other words, it doesn't work for children. I.E. "enemy01"
         spriteRend = GetComponent<SpriteRenderer>();
 
         if(spriteRend == null) {
             spriteRend = transform.GetComponentInChildren<SpriteRenderer>();
 
             if(spriteRend==null) {
                 Debug.LogError("Object '"+gameObject.name+"' has no sprite renderer.");
             }
         }
     }
 
     void OnTriggerEnter2D() {
         health--;
 
         if(invulnPeriod > 0) {
             invulnTimer = invulnPeriod;
             gameObject.layer = 10;
         }
     }
 
     void Update() {
 
         if(invulnTimer > 0) {
             invulnTimer -= Time.deltaTime;
 
             if(invulnTimer <= 0) {
                 gameObject.layer = correctLayer;
                 if(spriteRend != null) {
                     spriteRend.enabled = true;
                 }
             }
             else {
                 if(spriteRend != null) {
                     spriteRend.enabled = !spriteRend.enabled;
                 }
             }
         }
 
         if(health <= 0) {
             Die();
         }
     }
 
     void Die() {
         Destroy(gameObject);
     }
 
 }