Why is my character taking damage when attacking & why is it attacking multiple times per hit?

I use a trigger jump attack on my player. The problem is that when I touch the enemy once it takes 40 damage. My player also takes damage whenever I touch the enemy. MY player attack damge is set to 10

Problem Video

PlayerHealth

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 using UnityEngine.SceneManagement;
 using UnityEngine.UI;
 
 public class PlayerHealth : MonoBehaviour
 {
     public int startingHealth = 200, currentHealth;
     int amount;
     public Slider healthSlider;
 
     Animator anim;
     Player Player; //reference to Player Script
     bool dead;
     bool damage;
 
     // Start is called before the first frame update
     void Awake()
     {
         anim = GetComponent<Animator>();
         Player = GetComponent<Player>();
         currentHealth = startingHealth;
     }
 
     // Update is called once per frame
     void Update()
     {
         
     }
 
     public void TakenDmg(int amount)
     {
         damage = true;
 
         currentHealth -= amount;
         healthSlider.value = currentHealth;
 
         //anim.SetBool("Hurting", true);
 
         //if (!damage) TODO: Fix Hurting Animation off
         //{
         //    anim.SetBool("Hurting", false);
         //}
 
         if (currentHealth <= 0 ) {
             Death();
         }
 
     }
 
     public void Death()
     {
         dead = true;
     
         Destroy(gameObject, .5f); //TODO: add in the hurt animation
         Player.enabled = false; //stops player from moving when dead
         SceneManager.LoadScene("MainMenu"); //TODO: Create a wait a few seconds before returning to mainmenu
     }
 
 } //playerHealth

PlayerAttack

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class PlayerAttack : MonoBehaviour
 {
     public int attackdmg;
 
     // Start is called before the first frame update
     void Start()
     {
         
     }
 
     // Update is called once per frame
     void Update()
     {
         
     }
 
     void OnTriggerEnter2D(Collider2D other)
     {
         if (other.tag == "Enemy")
         {
             other.GetComponent<OpossumHealth>().damageTaken(attackdmg);
         }
     }
 
 
 
 }
 

OppossumHealth

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class OpossumHealth : MonoBehaviour
 {
     public int enemyHealth = 100, currentHealth;
 
     // Start is called before the first frame update
     void Start()
     {
         currentHealth = enemyHealth;
     }
 
     // Update is called once per frame
     void Update()
     {
         death();
     }
 
     public void death()
     {
         if (currentHealth <= 0)
         {
             Destroy(gameObject);
         }
     }
 
     public void damageTaken(int attackdmg)
     {
         currentHealth -= attackdmg;
     }
 
 }
 

OppossumAttack

 using System.Collections;
 using System.Collections.Generic;
 using UnityEngine;
 
 public class OpossumAttack : MonoBehaviour
 {
     public float timeattack = 1.5f;
     public int amount;
 
     GameObject PTarget;
     PlayerHealth PlayerHealth;
     bool playerRange;
     float timer;
 
     // Start is called before the first frame update
     void Start()
     {
         PTarget = GameObject.FindGameObjectWithTag("Player");
         PlayerHealth = PTarget.GetComponent<PlayerHealth>();
     }
 
     void OnCollisionEnter2D(Collision2D Opos)
     {
         if (Opos.gameObject == PTarget)
         {
             playerRange = true;
         }
     }
 
     void OnCollisionExit2D(Collision2D Opos)
     {
         if (Opos.gameObject == PTarget)
         {
             playerRange = false;
         }
     }
 
     // Update is called once per frame
     void Update()
     {
         attackTime();
     }
 
 
     void attackTime()
     {
         timer += Time.deltaTime;
 
         if (timer >= timeattack && playerRange)
         {
             attack();
         }
 
         //if (PlayerHealth.currentHealth <= 0)
         //{
         //    if (PTarget.tag == "Player"){
         //     Destroy(gameObject, 2f);
         //}
         //}
     }
 
     void attack()
     {
         timer = 0f;
 
         if (PlayerHealth.currentHealth > 0)
         {
             PlayerHealth.TakenDmg(amount);
         }
     }
 
 }//opoAttack