simple health decrease script?

hi Guys
I am making a platform game (first game) and I have some problems.
when i die (reload level) my HP isnt going down plz help me i dont know what to do.

here is my script:

using UnityEngine;
using System.Collections;

public class deathPoint : MonoBehaviour {

public int maxHP = 10;
public int currentHP = 10;
// Use this for initialization
void Start ()
{

}

// Update is called once per frame
void Update ()
{
if (gameObject.transform.position.y < 0)
{
Application.LoadLevel(0);

currentHP --;
}

if (currentHP <= 0)
{
Application.LoadLevel(1);
}

}
}

Welcome to the forum!

Please use code tags: http://forum.unity3d.com/threads/143875-Using-code-tags-properly

When you reload a level all game objects are deleted with the exceptions of the ones for which Unity - Scripting API: Object.DontDestroyOnLoad was called.
At the moment the game object which has this script is also deleted and after the loading you start again with the original value except if you use DontDestoyOnLoad.

An alternative is to use PlayerPrefs.