An object reference is required to access non-static member

 using UnityEngine;
 using System.Collections;
 
 public class EnemyHealthScript : MonoBehaviour {
     
     public int hp = 5;
     
     public bool isEnemy = true;
     
     void OnTriggerEnter2D (Collider2D collider) {
         
         ShotScript shot = collider.gameObject.GetComponent<ShotScript>();
         
         if (shot != null) 
         {    
             if (shot.isEnemyShot != isEnemy) 
             {        
                 hp -= shot.damage;
                 
                 Destroy(shot.gameObject);
                 
                 if (hp <= 0) 
                 {   SpecialEffectsHelper.Instance.Explosion(transform.position);
                     SoundEffectsHelper.Instance.MakeEnemyExplosionSound();
                     AddReduceMoney.cam.GetComponent<playerMoney>().addMoney (5);
                     Destroy(gameObject);                
             }
            }
           }
         }
 }
 

This isn't working, as the title says, and i don't know how to fix it