Animation NullReferenceException

I post this here because nobody helped me at answer section.And maybe I will explain more clear. I make a game, when my character have full life I play an animation, when it have 3 another animation and so on. But if I have 3 life instead of 4 I take this error when I leave the current scene and I go into another scene:
NullReferenceException: Object reference not set to an instance of an object
LifeControler.UpdateHP (Int32 life, System.Boolean& gameOver) (at Assets/Scripts/LifeControler.cs:34)
PlayerControlle.Start () (at Assets/Scripts/PlayerControlle.cs:41)
I know how to fix a normal NullReferenceException (you will see some example into scripts below) but this destroy my game. My life system and my game over text is broke. I hope you can help me.

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4. using UnityEngine.UI;
5. using UnityEngine.SceneManagement;
6.  
7. public class PlayerControlle : MonoBehaviour {
8.  
9.     public int speed;
10.  
11.     static public int gold;
12.     static public int currentLife;
13.     bool gameOver = false;
14.  
15.     public GameObject bolt;
16.     public GameObject boltUp;
17.     public GameObject boltSpawnRight;
18.     public GameObject boltSpawnLeft;
19.     public GameObject boltSpawnBack;
20.     public GameObject boltSpawnForward;
21.     public Text gameOverText;
22.  
23.     private float vertical;
24.     private float horizontal;
25.     private bool stopInput = false;
26.  
27.     private Rigidbody2D rb;
28.     private Animator animator;
29.     private LifeControler life;
30.  
31.  
32.  
33.     void Start () {
34.         rb = GetComponent<Rigidbody2D> ();
35.         animator = GetComponent<Animator> ();
36.         life = GetComponentInChildren<LifeControler> ();
37.         if (GlobalControl.Instance != null)
38.             currentLife = GlobalControl.Instance.CurrentLife;
39.         else if (GlobalControl.Instance == null)
40.             Debug.Log ("GlobalControl is null");
41.         life.UpdateHP (currentLife, out gameOver);
42.         if (gameOverText != null)
43.             gameOverText.text = " ";
44.     }
45.     private void OnDisable()
46.     {
47.         GlobalControl.Instance.CurrentLife = currentLife;
48.     }
49.     void Update () {
50.  
51.         if (horizontal > 0)
52.         {
53.             animator.SetTrigger ("playerMoveRight");
54.        
55.             if (Input.GetKeyDown (KeyCode.K))
56.                 Instantiate (bolt, boltSpawnRight.transform.position, Quaternion.Euler(new Vector3(0, 0, 0)));
57.         }
58.         if (horizontal < 0)
59.         {
60.            
61.             animator.SetTrigger ("playerMoveLeft");
62.             if (Input.GetKeyDown (KeyCode.K))
63.                 Instantiate (bolt, boltSpawnLeft.transform.position,  Quaternion.Euler(new Vector3(0, 180, 0)));
64.            
65.         }
66.         if (vertical > 0)
67.         {
68.            
69.             animator.SetTrigger ("playerMoveBack");
70.             if (Input.GetKeyDown (KeyCode.K))
71.                 Instantiate (boltUp, boltSpawnBack.transform.position,  Quaternion.Euler(new Vector3(0, 0, 0)));
72.            
73.         }
74.         if (vertical < 0)
75.         {
76.             animator.SetTrigger ("playerMoveForward");
77.             if (Input.GetKeyDown (KeyCode.K))
78.                 Instantiate (boltUp, boltSpawnForward.transform.position,  Quaternion.Euler(new Vector3(180, 0, 0)));
79.            
80.         }
81.         rb.velocity = new Vector2 (horizontal * speed, vertical * speed);
82.  
83.         if (vertical == 0 && horizontal == 0)
84.         {
85.             animator.SetTrigger ("playerIdle");
86.             if (Input.GetKeyDown (KeyCode.K))
87.                 Instantiate (boltUp, boltSpawnForward.transform.position,  Quaternion.Euler(new Vector3(180, 0, 0)));
88.         }
89.  
90.     }
91.     void FixedUpdate()
92.     {
93.         if(!stopInput)
94.             horizontal = Input.GetAxis ("Horizontal");
95.         if(!stopInput)
96.         vertical = Input.GetAxis ("Vertical");
97.         rb.velocity = new Vector2 (horizontal * speed, vertical * speed);
98.     }
99.  
100.  
101.     IEnumerator TakeDamage(int damageValue)
102.     {
103.         currentLife = currentLife - damageValue;
104.         life.UpdateHP (currentLife, out gameOver);
105.         if (gameOver) {
106.             stopInput = true;
107.             gameOverText.text = "Game Over" +
108.                 "\n Wait 5 seconds";
109.             yield return new WaitForSeconds (5);
110.             SceneManager.LoadScene (0);
111.         }
112.     }
113.     void OnTriggerEnter2D(Collider2D other)
114.     {
115.         if (other.gameObject.CompareTag ("EnemyBolt")) {
116.             StartCoroutine (TakeDamage (1));
117.             Destroy (other.gameObject);
118.  
119.         }
120.     }
121. }
122.  

Code (CSharp):

1. using System.Collections;
2. using System.Collections.Generic;
3. using UnityEngine;
4.  
5. public class LifeControler : MonoBehaviour {
6.  
7.     private Animator animator;
8.     private Vector3 position;
9.  
10.     void Awake()
11.     {
12.         position = transform.position;
13.     }
14.  
15.     void LateUpdate()
16.     {
17.         transform.position = position;
18.     }
19.     void Start()
20.     {
21.         animator = GetComponent<Animator> ();
22.         if (animator == null)
23.             Debug.Log ("Animator in LifeController is missing");
24.        
25.     }
26.  
27.     public bool UpdateHP(int life, out bool gameOver)
28.     {
29.         gameOver = false;
30.         switch (life) {
31.         case 4:
32.             return gameOver = false;
33.         case 3:
34.             animator.SetTrigger ("3Life");
35.             return gameOver = false;
36.         case 2:
37.             animator.SetTrigger ("2Life");
38.             return gameOver = false;
39.         case 1:
40.             animator.SetTrigger ("1Life");
41.             return gameOver = false;
42.         case 0:
43.             animator.SetTrigger ("Dead");
44.             return gameOver = true;
45.         default:
46.             Debug.Log ("LifeController error");
47.             return gameOver = true;
48.  
49.         }
50.     }
51. }
52.  

 

By the way, if you want another information feel free to ask