Error In Lives While Respawning

Hello Everyone! I'm making a 2 D plat former. When my player dies(falls below the ground the Lives decreases as 3,2,1,-1 & it should be 3,2,1,0. I am in this problem since the last month. I'm posting the codes below the Player controller and level manager script.
PLEASE PLEASE HELP ME!

using System.Collections; using System.Collections.Generic; using UnityEngine; public class PlayerController : MonoBehaviour {

 public float moveSpeed; 
 public Rigidbody2D myRigidbody;

 public float jumpSpeed;

 public Transform groundCheck;
 public float groundCheckRadius;
 public LayerMask whatIsGround;

 public bool isGrounded;

 private Animator myAnim;

 private Vector3 initScale;

 public Vector3 respawnPosition;

 public LevelManager theLevelManager;

 public GameObject stompBox;

 public float knockbackForce;
 public float knockbackLength;
 public float knockbackCounter;

 public float invincibilityLength;
 private float invincibilityCounter;

 // Use this for initialization
 void Start ()
 {
     myRigidbody = GetComponent<Rigidbody2D> ();
     myAnim = GetComponent<Animator> ();
     initScale = transform.localScale;

     respawnPosition = transform.position;

     theLevelManager = FindObjectOfType<LevelManager>();
 }
 // Update is called once per frame
 void Update () {
         
     isGrounded = Physics2D.OverlapCircle (groundCheck.position, groundCheckRadius, whatIsGround);

     if (knockbackCounter <= 0) 
     {

                 if (Input.GetAxisRaw ("Horizontal") > 0f) 
                {
                     myRigidbody.velocity = new Vector3 (moveSpeed, myRigidbody.velocity.y, 0f);
                     transform.localScale = new Vector3 (1f, 1f, 1f);
                     transform.localScale = new Vector3 (initScale.x, initScale.y, initScale.z);
                 } else if (Input.GetAxisRaw ("Horizontal") < 0f) {
                     myRigidbody.velocity = new Vector3 (-moveSpeed, myRigidbody.velocity.y, 0f);
                     transform.localScale = new Vector3 (-1f, 1f, 1f);
                     transform.localScale = new Vector3 (-initScale.x, initScale.y, initScale.z);
                 } else {
                     myRigidbody.velocity = new Vector3 (0f, myRigidbody.velocity.y, 0f);
                 }

                 if (Input.GetButtonDown ("Jump") && isGrounded)
         {
                     myRigidbody.velocity = new Vector3 (myRigidbody.velocity.x, jumpSpeed, 0f);
                 }
             
     }

     if (knockbackCounter > 0) 
     {
         knockbackCounter -= Time.deltaTime;

         if (transform.localScale.x > 0) 
         {
             myRigidbody.velocity = new Vector3 (-knockbackForce, knockbackForce, 0f);
         } else {
             myRigidbody.velocity = new Vector3 (knockbackForce, knockbackForce, 0f);
         }
     }

     if (invincibilityCounter > 0) 
     {
         invincibilityCounter -= Time.deltaTime;
     }

     if (invincibilityCounter <= 0) 
     {
         theLevelManager.invincible = false;
     }

     myAnim.SetFloat ("Speed", Mathf.Abs (myRigidbody.velocity.x));
     myAnim.SetBool ("Grounded", isGrounded);

     if (myRigidbody.velocity.y < 0) 
     {
         stompBox.SetActive(true);
     }else {
         stompBox.SetActive (false);
         }
 }

 public void Knockback()
 {
     knockbackCounter = knockbackLength;
     invincibilityCounter = invincibilityLength;
     theLevelManager.invincible = true;
 }


 void OnTriggerEnter2D(Collider2D other)
 {
     if (other.tag == "KillPlane") 
     {
         //gameObject.SetActive (false);

         //transform.position = respawnPosition;

         theLevelManager.Respawn ();
         //theLevelManager.healthCount = 0;
     }

     if (other.tag == "Checkpoint") 
     {
         respawnPosition = other.transform.position;
     }
 }

 void OnCollisionEnter2D(Collision2D other)
 {
     if (other.gameObject.tag == "MovingPlatform") 
     {
         transform.parent = other.transform;
     }
 }

 void OnCollisionExit2D(Collision2D other)
 {
     if (other.gameObject.tag == "MovingPlatform") 
     {
         transform.parent = null;
     }
 }

}

using System.Collections; using System.Collections.Generic; using UnityEngine; using UnityEngine.UI;

public class LevelManager : MonoBehaviour {

 public float waitToRespawn;
 public PlayerController thePlayer;

 public GameObject deathSplosion;

 public int coinCount;

 public Text coinText;

 public Image heart1;
 public Image heart2;
 public Image heart3;

 public Sprite heartFull;
 public Sprite heartHalf;
 public Sprite heartEmpty;

 public int maxHealth;
 public int healthCount;

 private bool respawning;

 public ResetOnRespawn[] objectsToReset;

 public bool invincible;

 public Text livesText;
 public int startingLives;
 public int currentLives;

 // Use this for initialization
 void Start () {
     thePlayer = FindObjectOfType<PlayerController> ();

     coinText.text = "Coins: " + coinCount; 

     healthCount = maxHealth;

     objectsToReset = FindObjectsOfType<ResetOnRespawn>();

     currentLives = startingLives;
     livesText.text = "Lives x " + currentLives;
 }
 
 // Update is called once per frame
 void Update () {
     if (healthCount <= 0 ) 
     {
         Respawn ();
         respawning = true;
     }
 }

 public void Respawn()
 {
     if (!respawning) {
         currentLives -= 1;
         livesText.text = "Lives x " + currentLives;

         if (currentLives > 0) {
             respawning = true;
             StartCoroutine ("RespawnCo");
         } else {
             thePlayer.gameObject.SetActive (false);
         }
     }
 }

 public IEnumerator RespawnCo()
 {
     thePlayer.gameObject.SetActive (false);

     Instantiate (deathSplosion, thePlayer.transform.position, thePlayer.transform.rotation);

     yield return new WaitForSeconds (waitToRespawn);

     healthCount = maxHealth;
     respawning = false;
     UpdateHeartMeter ();

     coinCount = 0;
     coinText.text = "Coins: " + coinCount;

     thePlayer.transform.position = thePlayer.respawnPosition;
     thePlayer.gameObject.SetActive (true);

     for (int i = 0; i < objectsToReset.Length; i++) 
     {
         objectsToReset [i].gameObject.SetActive (true);
         objectsToReset [i].ResetObject ();
     }
 }

 public void AddCoins(int coinsToAdd)
 {
     coinCount += coinsToAdd;

     coinText.text = "Coins: " + coinCount;
 }

 public void HurtPlayer(int damageToTake)
 {
     if (!invincible) 
     {    
                 healthCount -= damageToTake;
                 UpdateHeartMeter ();

                 thePlayer.Knockback ();
     }
 }

 public void UpdateHeartMeter()
 {
     switch (healthCount) 
     {
        case 6:
         heart1.sprite = heartFull;
         heart2.sprite = heartFull;
         heart3.sprite = heartFull;
         return;

     case 5:
         heart1.sprite = heartFull;
         heart2.sprite = heartFull;
         heart3.sprite = heartHalf;
         return;

     case 4:
         heart1.sprite = heartFull;
         heart2.sprite = heartFull;
         heart3.sprite = heartEmpty;
         return;

     case 3:
         heart1.sprite = heartFull;
         heart2.sprite = heartHalf;
         heart3.sprite = heartEmpty;
         return;

     case 2:
         heart1.sprite = heartFull;
         heart2.sprite = heartEmpty;
         heart3.sprite = heartEmpty;
         return;

     case 1:
         heart1.sprite = heartHalf;
         heart2.sprite = heartEmpty;
         heart3.sprite = heartEmpty;
         return;

     case 0:
         heart1.sprite = heartEmpty;
         heart2.sprite = heartEmpty;
         heart3.sprite = heartEmpty;
         return;

     default:
         heart1.sprite = heartEmpty;
         heart2.sprite = heartEmpty;
         heart3.sprite = heartEmpty;
         return;
     }
 }

}