Code not properly setting value to singleton C# Unity 4.6

I'm making a remake of 1981 Donkey Kong and I'm trying to increase the value of score when a barrel is destroyed or jumped over but for some reason my values are not being set properly when I check the values my score doesn't change and the livesleft goes from 3 to 2 just fine but once the scene reloads it stays at 2.

I just now thought it may have something to do with the code reloading the scene on death as the game manager script is on an empty gameobject that is a parent to the player character.

Here is the singleton script

 using UnityEngine;
 using System.Collections;
 using UnityEngine.UI;
 
 public class GameManager : MonoBehaviour {
     public Text livesleft;
     private static GameManager instance; 
     public int lives;
     public bool isdead;
     public bool haslostlife = false;
     public Text curScore;
     public int timesdied;
     public int highscore;
     public Text curhighscore;
     public static GameManager Instance{
         get
         {
             if(instance == null){
             GameObject go = new GameObject ("GameManager");
             go.AddComponent<GameManager>();
             }
         
         return instance;
         }    
     }
     public int score;
     void Awake()
     {
         instance = this;
         DontDestroyOnLoad(this.gameObject);
     }
 
     void OnEnable(){lives = 3;}
     void FixedUpdate()
     {
         //Debug.Log("Lives left" + lives);
         //Debug.Log("Times Died" + timesdied);
         Debug.Log("score = " + score);
             Debug.Log("high score = " + highscore);
         CheckLives();
         curScore.text = "" + score;
         if (score > highscore )
         {
             score = highscore;
             curhighscore.text = "" + highscore;
         }
     /*    if (timesdied == 2 && lives == 2)
         {
             lives = 1;
         }
         if (timesdied == 3){
             
         }*/
             
     }
     void CheckLives()
     {
         livesleft.text = "" + lives;
     }
 }

This script is on the Barrels, here is the relevant code.

         if (other.gameObject.tag == "Player"){
 
             player = other.gameObject;
             GameManager.Instance.timesdied = GameManager.Instance.timesdied + 1;
             GameManager.Instance.lives = GameManager.Instance.lives + -1;
             StartCoroutine(Restart ());
             
 
         }
         if (other.gameObject.tag == "HammerMode")
         {
             
             GameManager.Instance.score = GameManager.Instance.score + 500;
             Destroy(this.gameObject);
         }

  }

 IEnumerator Restart()
     {
         yield return new WaitForSeconds(3);
         Destroy(player);
         Application.LoadLevel("main");
 
     }

And from my Player Script (it uses a trigger below his feet to collide with the barrel for scoring):

     // In OnTriggerExit2D (collider other)
     if (other.gameObject.tag == "Barrel")
         {
             GameManager.Instance.score = GameManager.Instance.score + 100;
             Debug.Log ("Hey");
                 Debug.Log(GameManager.Instance.score);
         }